[1] Kullavanijaya P, Kulthanan K. Clinical efficacy and side effects of acitretin on the disorders of keratinization:a one-year study. J Dermatol, 1993, 20:501-506. [2] Marks R, Barton SP, Shuttleworth D, et al.Assessment of disease progress in psoriasis.Arch Dermatol, 1989, 125:235-240.