1. Novak ER, Jones GS, Jones HW: Novak's Textbook of Gynecology, Ed 7. Baltimore, Williams & Wilkins, 1965 p 495
2. Steck WD, Helwig EB: Cutaneous endometriosis. Clin Obstet Gynecol 9: 373, 1966
3. Eastman NJ, Hellman LM: Williams Obstetrics, Ed 13. New York: Appleton-Century-Crofts, 1966, p 88, 139, 148, 476
4. Scott RB, Te Linde RW: Clinical external endometriosis: Probable viability of menstrually shed fragments of endometrium. Obstet Gynecol 4: 502, 1954
5. Paull T, Tedeschi LG. Perineal endometriosis at the site of episiotomy scar. Obstet Gynecol 40: 28, 1972