1. Ballantyne, E. N.: Sacrococcygeal tumors: Adenocarcinoma of a cystic congenital embryonal remnant. Arch. Path.14: 1, 1932.
2. Birkett, J.: Contributions to the practical surgery of new growths or tumours. Guy’s Hosp. Rep.5: 247, 1859.
3. Dukes, C.: Submucous implantation cysts of the rectum. Proc. Roy. Soc. Med.22: 715, 1929.
4. Edwards, M.: Multilocular retrorectal cystic disease—cyst-hamartoma: Report of twelve cases. Dis. Colon & Rectum.4: 103, 1961.
5. Esterly, J. R., and O. M. Baghdassarian: Presacral neurenteric cyst: An unusual malformation resulting from persistence of the neuroenteric canal. Bull. Johns Hopkins Hosp.113: 202, 1963.