Hasabe RA, Tripathi NS, Kesarkodi P. Menstruating umbilicus: secondary subcutaneous umbilical endometriosis: a rare case report. Int J Reprod Contracept Obstet Gynecol [Internet]. 2022 May 26 [cited 2025 Dec. 4];11(6):1814-7. Available from: https://www.ijrcog.org/index.php/ijrcog/article/view/11692