1. Anal tuberculosis. A report of two cases;Ahlberg;Acta Chir Scand,1980
2. Perianal Crohn’s disease;Alexander-Williams;World J Surg,1980
3. Perianal hidradenitis sup purativa;Anderson;Dis Colon Rectum,1958
4. Relationship between Bowen’s disease and internal malignant tumors;Anderson;Arch Dermatol,1973
5. Extramammary Paget’s disease;Anthony;Clin Exp Dermatol,1986