1. L. Musajo, Ann. Ist. Super. Sanita 376 (1969) and references therein.
2. M. A. Pathak, J. H. Fellman and K. D. Kaufman, J. Invest. Dermatol. 35, 165 (1960).
3. N. Mizumo, S. Tsuneishi, S. Matsuhashi, S. Kimura, Y. Fujimma and T. Ushijima, in “Sunlight and Man” (edited by M. A. Pathak, et al.), p. 389 (1974), Univ. of Tokyo Press, Tokyo.
4. A. C. Giese, Photophysiology 6, 11 (1971) and references therein.
5. W. L. Fowlks, D. G. Griffith and E. L. Oginsky, Nature 181, 571 (1958).