1. Harris, Seale: J.A.M.A. 83:729, 1924
2. Harris, Seale: Ann. Int. Med. 10:515, 1936.
3. Harris, Seale: Am. J. Dig. Dis. 2:557, 1935.
4. Bockus, H. L. Gastroenterology, Vol. III, pgs. 740, 812., Saunders.
5. Sippe, C., Bostock, J: Med. J. of Australia, 1:7, 207, 1033.