Portnoy, B.; Beck, M. The Treatment of Active Chronic Psoriasis: A Comparison of the Effectiveness of a Preparation Containing 0.1% Dithranol and 17% Urea in a Cream Base and 0.1% Dithranol in Lassar´s past B.P.C. Acta Derm Venereol 1981, 61, 459-461.