Kuokkanen, K., M. Alavaikko, and R. Pitkänen. “Hyperkeratosis Lenticularis Perstans (Flegel´s Disease)”. Acta Dermato-Venereologica 63, no. 4 (July 1, 1983): 357–360. Accessed July 11, 2026. https://medicaljournalssweden.se/actadv/article/view/7921.