Portnoy, B. and Beck, M. (1981) “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 Dermato-Venereologica, 61(5), pp. 459–461. doi: 10.2340/0001555561459461.