1. H. Bailey(1958 ), "Emergency Surgery ". 7th Edition . Bristol, John Wright & Sons Ltd., page315 .
2. H. Bailey, and R. J. Mcn. Love(1956 ), "A Short Practice of Surgery ". 10th Edition . London, H. K. Lewis & Co Ltd., page322 .
3. Acute cholecystitis
4. F. Christopher(1946 ), "A Textbook of Surgery ". 4th Edition . Philadelphia, W. B. Saunders Co., page1128 .