Comparision of the pharmacokinetics and phototoxicity of protoporphyirn IX metabolized from 5-aminolevulinic acid and two derivatives in human skin in vivo. - Gerscher,S.; Connelly,J.P.; Griffiths,J.; Brown,S.B.; MacRobert,A.J.; Wong,G.; Rhodes,L.E. (Photochem Photobiol, 2000)