Snellman, Erna, and Tapio Rantanen. “Kinetics of Phototoxicity in Trioxysalen Bath Psoralen Plus Ultraviolet A Photochemotherapy”. Acta Dermato-Venereologica, vol. 81, no. 3, May 2001, pp. 171-4, doi:10.1080/000155501750376230.