UVA irradiation following treatment with topical 8-methoxypsoralen improves bleomycin-induced scleroderma in a mouse model, by reducing the collagen content and collagen gene expression levels in the skin, Hayashi S, Ikeda MKitamura YHamasaki YHatamochi A, J Dermatol Sci, 67(1), 20-5, Jul. 2012