1. Eisendrath, D. N. and Rolnick, H. C.: Textbook of Urology, 2nd ed. Philadelphia: J. B. Lippincott Co., p. 400.
2. Young’s Practice of Urology;Young,1926
3. Clinical Urography;Braasch,1951
4. Gray’s Anatomy of the Human Body, 21st ed. Philadelphia: Lea & Febiger.