1. Americans know more than ever today about sun safety-but keep on tanning;Sun Skin News,1994
2. Less tanning now lowers cancer rate later;Kubetin;Skin Allergy News,1994
3. Sunlight and health;Emerson;Am J Public Health,1933
4. The geographical distribution and aetiology of rickets;Palm;Practitioner,1890
5. Niels Ryberg Finsen, 1903;Howell,1990