Tania Anne Woloshyn
Search for other papers by Tania Anne Woloshyn in
Current site
Google Scholar
Dead points

Contained within the closed stores of the Wellcome Library is an unusual painting about light therapy, made by a now-obscure British artist, Beatrice Langdon. In 1938 she painted the Light Department of the Royal London Hospital, a work commemorating the impact of the Finsen lamp in the battle against tuberculosis of the skin (lupus vulgaris). Produced almost four decades after the institutionalisation of light therapy in Britain (1899), Langdon’s painting depicts the original, and by now obsolete, version of Finsen’s carbon arc lamp at a moment when the London Hospital was to refit new, smaller and more efficient lamps. The exact reasons for Langdon’s painting are, however, unknown, and this concluding chapter leads off from the mysteries and loose threads surrounding the work to discuss the many other silences, absences, and dead ends in the history of light therapy. It also explores contemporary images - a photograph by Danish photographer Nicolai Howalt and a campaign poster by Cancer Research UK and Nivea - to consider the UK’s ongoing ambivalent relationship with actinic light, which remains at once a source of health and of risk.

In dealing with the effect of the Sun’s rays on our bodies we have to bear in mind that every good thing in this world, whatever its nature – everything we come to regard as a blessing – contains within itself the power of its own destruction, if misused, that is wrongly used, or abused, that is, used in excess. A drug may cure – and the same drug may kill. […] So it is with the Sun’s rays.1

(Edward J. Deck, 1926)

The sun has got his hat on, hip-hip-hip-hooray.

The sun has got his hat on and he’s coming out today.

Now we’ll all be happy, hip-hip-hip-hooray.

The sun has got his hat on and he’s coming out today.

He’s been tanning niggers, out in Timbuktu.

Now he’s coming back, to do the same to you.

So jump into your sunbath, hip-hip-hip-hooray.

The sun has got his hat on and he’s coming out today.2

(Ralph Butler and Noel Gay, ‘The Sun Has Got His Hat On’, 1932)

From the din of a bare, expansive room, scattered white shapes and bright vermillion blotches emerge and demand our attention (Plate 8). It is an otherwise calm, even dull scene, the stillness conveyed by the rigid, upright poses of several composed nurses and their limp horizontal patients. Beatrice Langdon’s oil painting, The Finsen Light Treatment at the London Hospital of c. 1938, is an unusual and mysterious work, now contained in the closed stores of the Wellcome Library. Little is known about Langdon, and there is no evidence as to why she made this painting.3 Produced almost four decades after the institutionalisation of light therapy in Britain (1900), Langdon’s painting depicts the original, and by now obsolete, versions of Finsen’s carbon arc lamp at a moment when the London Hospital was to refit new, smaller, and more efficient lamps in its light department.4 Acting as a kind of commemorative portrait of the Finsen lamp and its impact in the battle against lupus vulgaris, the painting included a choice, off-handed phrase by Queen Alexandra that was etched into the wall of the newly completed department in 1903: ‘Nothing like perseverance.’5 The remark was no doubt intended to encourage both patient and nurse. A year earlier, it was noted in the BMJ that,

Each sitting lasts an hour and a quarter on, it may be, two or three hundred different days or even more. Thus the course of treatment for the [lupus vulgaris] patient means a substantial slice out of his life and the individual sitting for the nurse means an hour of constant strain of attention and a large amount of muscular fatigue.6

Prized for their meticulous attention to detail and high degree of skill, nurses were the primary operators of the Finsen lamp. Though Langdon’s painting gives prominence to the large central lamps, detailing their metal supports, telescopic brass arms, red skirting, and scattered white light, the true figures of the work are the nurses. The patients, by comparison, appear ghostly and unfinished, barely noticeable next to their attendants’ crisp white uniforms and goggled faces.

Langdon’s choice of medium may be a rarity – it is the only British painting of light therapy I have seen – but her choice of subject is certainly not. The nurse is a ubiquitous figure in the visual culture of light therapy, ever present in archival photographs as an observant technophile or intimate carer (Figs. 1.3, 1.10, 2.6, 2.82.9, 3.1, 3.113.13, 3.163.17, 4.3, 4.15). Yet her role was only marginally discussed in the medical literature; highly visible in images, seemingly invisible in texts. The role of nurses in light therapy’s development has only recently begun to be addressed, and they are among many ‘invisibles’ in its history that deserve further attention: Langdon, Edith Tudor-Hart, Dr Dora Colebrook, the all-female staff of the SLHWC, and even Queen Alexandra, these are important female agents who actively contributed to the therapy’s development and dissemination in late nineteenth- and early twentieth-century Britain.7

Equally silent are the voices of patients, especially children, and of various members of the public who consumed home-use lamps and their emanating ultraviolet light.8 Furthermore, who were the anonymous photographers providing images for key practitioners, institutions, and the press? Where are the archives of now-defunct manufacturers? And what of the therapy’s ‘other’ subjects – those bodies of ‘colour’ in Chapter 5 – who proved so valuable to practitioners’ perceptions of suntan? Was light therapy really only ever a ‘white’ therapy, the privilege of those whose skin readily consumed ultraviolet radiation and pigmented?

Dr Murray Levick, describing light-therapy experiments he carried out at St Thomas’ Hospital on child patients exhibiting ‘debility, with anorexia, listlessness, general malnutrition and fretfulness’, stated in 1924: ‘It was interesting to note that a little negro boy made very tardy progress alongside a white boy who made a rapid recovery.’9 Since solar erythema (Chapter 1) and pigmentation (Chapter 4) on white skin became the visible standards with which to measure therapeutic progress, dark skin remained – and remains to this day – either a foil or a ‘problem’.10 With their resistant bodies and troubling skin, dark subjects refuse to assimilate to normative (white) treatments of light exposure, presenting a dead end to the practitioner.

In Chapter 5 I briefly mentioned another, related dead end for practitioners: excessive pigmentation in the white patient. For Dr Franz Thedering, too deep a suntan could inhibit further curative effect. The deep tan, acting as a protective ‘coat of armour’, impeded the body’s absorption of ultraviolet radiation, signalling a dead end or plateau during treatment.11 Dr William Beaumont called this the ‘dead point’.12 From this point treatment would stop, and the skin would be allowed time to rest and recover. Once the skin lost its tan, the treatment would start again, creating cycles of ‘dead points’ and recoveries.

Looking back on this today with hindsight, the phrase ‘dead point’ is particularly apt, especially in relation to messages from Cancer Research UK about sunburn and suntan as explicit, and potentially life-threatening, forms of bodily damage. As an initial inhibitor to progressing forward, the ‘dead point’ finds resonance with light therapy’s numerous historical dead ends. In this book I have put medical practitioners in the driver’s seat. This is not to say, however, that it was a smooth or easy journey for them, or an unaccompanied one. Artists, patients, members of the public, and manufacturers came along for the ride.13 The difficulty of finding their voices revolves around access: limited or non-existent sources, restricted archives, and lost memories.14 Silences, absences, loose threads, and dead ends are prevalent in this largely understudied topic.

So too could we view the key images discussed in each chapter as ‘failures’. After being introduced to light therapy through images collapsing the distinction between medical and popular exposures in Chapter 1, we looked at poorly ‘fixed’ photographs of solar erythema in Chapter 2 and damaged photographs in Chapter 3. In Chapter 4, montages of lamps and their invisible emanating energies confounded us further, and in Chapter 5 we were dazzled by colour pamphlets of models less bronzed than fluorescent. All of these images might be said to have failed to disseminate the therapy’s efficacies and methods clearly and legibly. Yet, as the book has argued throughout, the intersection of art and medicine need not be fluid or seamless. The images and objects are fascinating and significant precisely because they are problematic: confounding, ambiguous, and perplexing. Resistant and wily, they instead communicate vital information about practitioners’ anxious investment to substantiate light therapy’s many values: its medical ‘worth’, which practitioners struggled to establish through dosage standardisation amidst damning reports and contradictory exposure methods; its social ‘aims’, not least its claim to regenerate a ‘sun-starved’ nation of ‘C3’ citizens through the use of potentially lethal home-use lamps; and to do this aesthetically through gradations of ‘luminosity’, using black-and-white photographs to represent the variable red hues of sunburn, overexposed photographs and fantastical montages that obscure the therapeutic process, and saturated colour pamphlets in which white models become radioactive ‘primitives’. Such values are embedded within these images, material objects shot, snipped, and printed to become complex and complicated things. As Alan Mayne put it:

a great deal of material culture evidence – because it is fragmentary and incomplete, or because of its scale and volume, or its imperfect fit with other historical sources – is profoundly opaque and unfamiliar to interpreters in the present day. […] That is their value. It is because material culture is not simple and transparent in its meanings that the effort required to comprehend its full complexity and to compare it usefully with other sources translates into open-ended research questions which [sic] can extend our understanding of past societies and habitats.15

What of the present? Can looking at the past, especially through images and objects, prove useful to thinking about our ambivalent relationship with natural and artificial sunlight today? Conversely, can contemporary images help us to rethink the past?

As of April 2011, UK legislation has prohibited sunbed usage to people under eighteen, in an effort to protect British youth from ultraviolet radiation exposure. It emerged amidst fears of a new beauty ‘addiction’ for the euphoric highs of tanning, termed ‘tanorexia’.16 Two years later, Cancer Research UK asked image-conscious British girls, ‘R UV Ugly?’ Its SunSmart campaign employed the terms ‘ugly’ and ‘ageing’ synonymously to educate the public about the damaging effects of ultraviolet light. It was a bold attempt to wrest apart the long-standing association between tanned skin, beauty, and youthfulness that continues to fuel a flourishing tourism industry to sunny locales abroad and the tanning industry in the UK. Meanwhile, rising concern about vitamin-D deficiency among children has forecast the ‘return’ of rickets, prompting mixed views from the medical community and the media.17 Light therapy for mental health, in the treatment of SAD and depression, and its ongoing use for dermatological conditions indicates it remains within mainstream medicine. In 2016, Prima magazine informed its middle-class, middle-aged female readers that, among its ‘16 Simple Steps to Help You Feel Fitter, Healthier and Happier Every Day’, number 7 was ‘Wear sunscreen every day’ and number 8 was ‘Don’t be D-ficient’.18 It is but one of many examples of popular literature, sourcing the latest medical advice, recommending both protection from and exposure to sunlight. With such conflicting messages rife within the medical community and disseminated to the public, can we definitively answer the question: is sunlight good or bad for our health and that of our children?

Crucially, as I have argued in this book, the contemporaneous and contradictory array of attitudes – of fear versus desire – towards the therapeutic value of natural and artificial light is not a new phenomenon. ‘Indeed the history of bodies and sunlight is one of controversy and disagreement’, to quote Simon Carter.19 Such controversy and disagreement can in part be attributed to competing conceptions of what light, and especially its ultraviolet radiation, is and how it acts upon our bodies: as a ‘stimulant’ analogous to a drug, according to Dr Edward Deck (epigraph); as a ‘bandage’ (pansement) for Dr Auguste Rollier; as a vital ‘food’ to be consumed; and as a destroyer, whether as a bactericide, disinfectant, or carcinogen. Little wonder light therapy’s history is marked by ambiguities, tensions, and contradictions, it is a treatment premised upon harnessing an ephemeral, invisible, if not outright uncontrollable, natural source.

To conclude, I want to discuss two very different contemporary images about light exposure, both of which inform and are informed by light therapy’s history (Figs. 6.16.2). The first is from Danish photographer Nicolai Howalt’s series, ‘Light Break’ (Fig. 6.1).20 Howalt gained intimate access to the Finsen archive in the Medical Museion (Copenhagen), borrowing pieces of original phototherapy equipment such as lenses and telescopic arms from Finsen lamps, and produced photographs of them. Indeed, he did not simply make photographs of them, but with them, strapping the focusing lenses to his camera and aiming it at the sun. Beautiful aesthetic ‘accidents’ resulted, producing abstract swirls and scatterings typical of lens flare (Chapter 2).

6.1 Nicolai Howalt, Light Break #1, 2013.

Inkjet print. © Nicolai Howalt.

6.2 Nivea and Cancer Research UK campaign poster, 2013

CRUK and Nivea SUN.

Howalt’s photographs and photograms visualise the ‘injurious’ rays and present them as the main photographic subject. These are as much portraits as Finsen’s before and after photographs of his patients (Figs. 2.4, 2.7), but here Howalt made portraits of actinic light, of its fickle, powerful, and destructive character. The broken, shattered, refracted light made visible with Finsen’s equipment signals Howalt’s open engagement with chance and uncertainty. It is playful and uncontrolled in contrast to Finsen’s rigorous experimentation with actinic light. Yet in doing so Howalt actively ‘brings to light’ the forgotten, obscure, and largely hidden archival equipment and documentation in the Finsen archive to a new audience. The hypnotising, swirling vortex of Light Break #1 doubles as a transfixed pupil (Fig. 6.1). It is an unplanned but fitting likeness, since Howalt’s project aestheticises therapeutic light’s blinding action. Figure 6.1 is, put simply, a work of beautiful damage. It enables us to reconceptualise Finsen’s healed lupus vulgaris patients as the same, their beautifully cicatrised skin produced by destructive light. Howalt’s project is thus an instance of contemporary art allowing us to revisit medicine’s past with fresh insight.

The second image is from a series of health campaign posters from 2013 created by the agency Draft FCB for a partnership between the skin-care company Nivea and Cancer Research UK (Fig. 6.2). Anthropomorphised with a button nose, gigantic smiling mouth, black eyes, and rosy cheeks, an enormous sun fills a third of the poster’s composition.21 It – or rather ‘he’ – is absurdly out of proportion with the scale of the rest of the landscape. With disembodied hands the sun benevolently instructs a white child, dressed for snorkelling in the sea, to observe the length of his shadow: the shorter the shadow, the stronger the sun’s emanating rays. They burst forth in strong graphic blocks of white and yellow, reminiscent of the Art Deco rays in the 1936 ‘Vi-tan’ pamphlet cover (Plate 1).

Not an advertisement per se, the poster promotes no actual product, unless we consider the shade a desirable commodity. There are subtle references to the Nivea brand, specifically the blue and white beach balls, and to Blackpool tourism, such as the inclusion of Blackpool Tower and a ‘Kiss me quick’ souvenir hat. The phrase ‘Kiss me quick’ is here cleverly employed both as a nostalgic signifier (of a bygone era of kitsch beach culture so strongly tied to Blackpool’s history) and as another instruction, to literally make contact with the sun briefly (becoming ‘sun-kissed’), an exciting and even naughty quick encounter of bodily contact with sunlight. Significantly, Draft FCB’s creatives were inspired by the saucy seaside postcards of Donald McGill (1875–1962), an artist who faced charges for breaking the Obscene Publications Act (1857) in the 1950s.

The poster’s caption reads, ‘The sun has got his hat on, he’s coming out today … If your shadow is shorter than you, the shade is where to play!’ It is an excerpt of altered lyrics from Ralph Butler and Noel Gay’s 1932 song, ‘The Sun Has Got His Hat On’. The second epigraph above provides the original lyrics in full. Encouraging listeners to soak up the sun’s rays by submerging themselves in a sunbath – and enjoy it – the song typifies interwar perceptions of bodily exposure to light as a liberating, pleasurable, and healthful act. Yet seeping through the negrophiliac joy (now offensive racism) in the third couplet is a forewarning characteristic of the ambivalence towards excessive exposures and deep tans as acts of racial transgression, even degeneration.22 Like Baumer’s Punch cartoon (Fig. 5.2), the sun’s transformative power is at once desirable and worrying, unfixing the supposedly unalterable racial distinction between white and black.

The campaign’s reference to the overly sexualised art of McGill (in a campaign directed towards children) and its use of Butler and Gay’s negrophiliac song to communicate sun safety are puzzling, as is the ‘voice’ of instruction, that of the sun himself.23 Deck likewise advocated practising moderation eighty-seven years earlier (see epigraph). Now the likes of Nivea facilitate, nay encourage, prolonged access to the sun through the consumption of sunscreen.24 At once helpful and potentially lethal, the sun in this poster is represented as a jovial, carcinogenic force; he may appear benevolent, but can he truly ever be ‘benign’?

This dual characterisation of the sun – as a source simultaneously of pleasure, happiness, and health but also of cancer, pain, and bodily damage – epitomises Britain’s messy past and present relationship with sunlight. Like Rima Apple in Vitamania, I predict no simple resolution, only more contradictory data, and along with its many unanswered questions and mysteries (Langdon’s painting included, Plate 8), surely why the subject will continue to fascinate practitioners and public alike. As Lavine put it, ‘things that are controversial, or at least unsettled, are less likely to cede the spotlight’.25 With a visual culture full of unstable representations, light therapy is nothing if not ‘unsettled’, and I encourage scholars to further explore, with new methods, fresh energy, and perseverance, the British body’s fickle love of the light.


1 Bold original. Edward J. Deck, The Sun and How to Use It (London: Sunlight League, 1926), p. 3.
2 Originally performed by Ambrose and His Orchestra, with vocals by Sam Browne.
3 Born in Manchester (1898) and educated at the prestigious St Paul’s Girls’ School in Hammersmith (London), Langdon went on to study fine art at the Byam Shaw and Vicat Cole School of Art in Kensington. Her paintings were exhibited at the Royal Academy, Royal Institute of Oil Painters, Royal Society of British Artists, New English Art Club, and the Paris Salon, with one solo show at the Arlington Gallery in 1930. Regarding Plate 8, in 1952 she offered the painting to the Wellcome Trust, accepting £40 for it (approximately £1,100 in 2016, www.thisismoney.co.uk/money/bills/article-1633409/Historic-inflation-calculator-value-money-changed-1900.html [accessed 9 September 2016]). In its archival file there are letters describing her as a well-known artist during this period. She died in 1986, unmarried and childless. See David Buckman, Artists in Britain since 1945 (Bristol: Art Dictionaries, 2006), vol. I, p. 17; The Times, 11 March 1930, p. 14; The Times, 10 January 1986, p. 24; Wellcome Library Archives, WA/HMM/Co/Chr/J.126, ‘L, 1932–52’, ‘Langdon, Miss B’.
4 Anne Kinloch Jamieson, ‘An Intolerable Affliction: A History of Lupus Vulgaris in Late Nineteenth- and Early Twentieth-Century Britain’ (Ph.D. dissertation, University of Leeds, 2010), pp. 108–9.
5 P. H. Oakley Williams, ‘A Day’s Work at “The London”’, Pall Mall Magazine (May 1903), pp. 68–2, at p. 73.
6 ‘The Present Position of the Light Treatment of Lupus’, BMJ, 4 January 1902, pp. 44–7, at p. 44. See also Finsen, Phototherapy, p. 74; and Jamieson, ‘An Intolerable Affliction’, p. 74.
7 See Jamieson, ‘An Intolerable Affliction’; Tanya Woloshyn, ‘Nursing with Flare: The Operators of Light Therapy, c. 1890–1940’, Dermatological Nursing, 15:1 (2016), 49–54; and Tanya Woloshyn, The Kiss of Light: Nursing and Light Therapy in 20th-Century Britain (London: Florence Nightingale Museum, 2015).
8 See also Susan E. Lederer, Subjected to Science: Human Experimentation in America before the Second World War (Baltimore, Md.: Johns Hopkins University Press, 1995), p. xvi.
9 Cited in Hill, ‘The Physiological Effects of Light’, Proceedings of the Royal Society of Medicine, 17 (1924), 15–21, at p. 20. See also Richard Dyer, White (London and New York: Routledge, 1997), pp. 1–2; and a photograph of Alma Smith modelling in lingerie under an unlit mercury vapour lamp, titled Her Daily Sunbath. The caption reads, ‘Miss Alma Smith the 23-year-old actress who is considered to be the cleverest Soubrette of the coloured race and who recently arrived from America to join the cast of the “Blackbirds” at the London Pavilion snapped at her daily sunbath of ultra violet rays. For the past few months Miss Smith has been the sensation of New York where she has become known as “The Little Bunch of Personality.” Her recent song hits “Banana Anna” and “Hot Poppa be Yourself” together with her Blackbottom dancing are the chief cause.’ Greater Manchester County Archives, GB124.DPA/1129/15, [General Photographic Agency, Fleet Street], photograph, c. 1926.
10 A group of phototherapy nurses explained to me that dark skin remains a ‘problem’ when judging erythema and pigmentation production, since white skin is the ‘norm’. The South-East of England Phototherapy Network’s 21st Update Meeting, St Thomas’ Hospital, 15 October 2015. See also Roberta Bivins, ‘The “English Disease” or “Asian Rickets”? Medical Responses to Postcolonial Immigration’, Bulletin of the History of Medicine, 81:3 (2007), 533–68.
11 Franz Thedering, Sunlight as Healer: A Popular Treatise (Slough: Sollux, 1926), p. 24.
12 William Beaumont, Fundamental Principles of Ray Therapy (London: H. K. Lewis & Co., 1931), p. 95. Similarly, Katherine Gamgee described the patient’s tanned, unresponsive skin as ‘stale’ and recommended a similar cyclical pattern of alternating irradiation and rest. Katherine Gamgee, The Artificial Light Treatment of Children (London: H. K. Lewis & Co., 1927), p. 111.
13 On public appropriations of medical concepts, see Matthew Lavine, The First Atomic Age: Scientists, Radiations, and the American Public, 1895–1945 (New York: Palgrave Macmillan, 2013), pp. 7, 9; and Nancy Tomes, The Gospel of Germs: Men, Women, and the Microbe in American Life (Cambridge, Mass.: Harvard University Press, 1998), p. 13.
14 On the difficulty of accessing silent voices, see also Margarete Sandelowski, Devices and Desires: Gender, Technology, and American Nursing (Chapel Hill, NC: University of North Carolina Press, 2000), p. 15; and Joel D. Howell, Technology in the Hospital: Transforming Patient Care in the Early Twentieth Century (Baltimore, Md.: Johns Hopkins University Press, 1996), p. 12.
15 Alan Mayne ‘Material Culture’, in Simon Gunn and Lucy Faire (eds), Research Methods for History (Edinburgh: Edinburgh University Press, 2012), pp. 48–65, at p. 56.
16 See, for example, Daniel Martin, ‘The Tanorexia Timebomb: Sunbeds Blamed as Skin Cancer Soars in Young Women’, Daily Mail, 8 April 2009, www.dailymail.co.uk/news/article-1168407/The-tanorexia-timebomb-Sunbeds-blamed-skin-cancer-soars-young-women.html (accessed 27 March 2016). See also Dorothy Porter, ‘The Healthy Body’, in Roger Cooter and John Pickstone (eds), Medicine in the Twentieth Century (Amsterdam: Harwood Academic Publishers, 2000), pp. 201–16.
17 Bivins, ‘The “English Disease” or “Asian Rickets”?’
18 ‘16 Simple Steps to Help You Feel Fitter, Healthier and Happier Every Day’, Prima (January 2016), p. 83. See also ‘No Safe Way to Suntan, New NICE Guidance Warns’, BBC News, 9 February 2016, www.bbc.co.uk/news/uk-35529596 (accessed 24 March 2016).
19 Simon Carter, Rise and Shine: Sunlight, Technology and Health (New York and Oxford: Berg, 2007), p. 27.
20 Nicolai Howalt, Light Break: Photography/Light Therapy (Copenhagen: Fabrik Books, 2015).
21 The sun has been anthropomorphised as a physician and photographer since the 1800s. See Melissa Miles, The Burning Mirror: Photography in an Ambivalent Light (North Melbourne: Australian Scholarly Publishing, 2008), pp. 82–4; Zane R. Kime, Sunlight (Penryn: World Health Publications, 1980), p. 36; and J. M. Andress and W. A. Evans, Success and Health (Toronto: Ginn & Co., 1925), p. 117.
22 In 2014, DJ David Lowe was fired for playing this song because of its racist language. ‘BBC Radio Devon DJ David Lowe Loses Job over Racist Word’, BBC News, 11 May 2014, www.bbc.co.uk/news/uk-england-devon-27360884 (accessed 24 March 2016).
23 By analysing this image I do not want to suggest that Nivea, CRUK, or this agency did anything necessarily ‘wrong’ or ‘bad’ in their choices for this campaign poster; rather, I want to make it clear that making historical references – to historical objects, places, songs, and artwork – when it comes to ultraviolet exposure and sun safety can only be ambiguous and unsettling because they are the products of a problematic past.
24 Dunne Romano posits sunscreen as the ‘compromise between sun avoidance and sun worship’, in Sally Dunne Romano, ‘The Dark Side of the Sun: Skin Cancer, Sunscreen and Risk in Twentieth-Century America’ (Ph.D. dissertation, Yale University, 2006), p. 257.
25 Lavine, First Atomic Age, p. 200.
  • Collapse
  • Expand

All of MUP's digital content including Open Access books and journals is now available on manchesterhive.


Soaking up the rays

Light therapy and visual culture in Britain, c. 1890–1940


All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 1192 237 5
PDF Downloads 0 0 0