Karrer, Sigrid, Rolf-Markus Szeimies, Wolfgang G. Philipp-Dormston, Peter A. Gerber, Welf Prager, Elisabeth Datz, Florian Zeman, Karolina Müller, and Michael Koller. 2021. “Repetitive Daylight Photodynamic Therapy Versus Cryosurgery for Prevention of Actinic Keratoses in Photodamaged Facial Skin: A Prospective, Randomized Controlled Multicentre Two-Armed Study”. Acta Dermato-Venereologica 101 (1):adv00355. https://doi.org/10.2340/00015555-3717.