Tarstedt, M. et al. 2005. A randomized multicenter study to compare two treatment regimens of topical methyl aminolevulinate (Metvix)-PDT in actinic keratosis of the face and scalp. Acta Dermato-Venereologica. 85, 5 (Sep. 2005), 424–428. DOI:https://doi.org/10.1080/00015550510032887.