1. Cunninghams Manual of Practica Anatomy-Page 135. Vol.-3. Head & Neck & Brain, Edited by G. J. Romanes, Fifteenth edition Reprint 1990 ELBS.
2. Gray’s Anatomy-Page 736 & 797 Edited by Ptter L. Williams & Mary Dyson Edition 37th -1993 ELBS with Churchill Livingstone.