Bjørndal Sørensen, Kristine, and Kristian Thestrup-Pedersen. “Pityriasis Rubra Pilaris: A Retrospective Analysis of 43 Patients”. Acta Dermato-Venereologica, vol. 79, no. 5, Sept. 1999, pp. 405-6, doi:10.1080/000155599750010517.