1. Cutaneous endometriosis;Agrawal;Singapore Med. J.,2008
2. Spontaneous cutaneous umbilical endometriosis: report of a new case with immunohistochemical study and literature review;Kyamidis;Dermatol. Online J.,2011
3. Menstruating from the umbilicus as a rare case of primary umbilical endometriosis: a case report;Bagade;J. Med. Case Rep.,2009
4. Extrapelvic endometriosis;Markham;Obstet. Gynecol. Clin. North Am.,1989
5. Endometriosis of the umbilicus;Mann;IMJ III Med. J.,1964