Neumann, E, R Nilsson, and U. Paul. “Hyperkeratosis Lenticularis Perstans (Flegel)”. Acta Dermato-Venereologica 54, no. 6 (November 1, 1974): 475–478. Accessed June 21, 2026. https://medicaljournalssweden.se/actadv/article/view/17725.