Beckman, L, K Bergdahl, B Cedergren, MG Damber, S Lidén, B von Schoultz, and T. Stigbrand. 1977. “Increased Serum Levels of the Pregnancy Zone Protein in Psoriasis”. Acta Dermato-Venereologica 57 (5):403-6. https://doi.org/10.2340/0001555557403406.