Hasabe, Rakesh A., Neha S. Tripathi, and Prajakta Kesarkodi. “Menstruating Umbilicus: Secondary Subcutaneous Umbilical Endometriosis: A Rare Case Report”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology 11, no. 6 (May 26, 2022): 1814–1817. Accessed December 4, 2025. https://www.ijrcog.org/index.php/ijrcog/article/view/11692.