1. Lahey Clin;ALLAN, F.M.;Bull,1946
2. ALVAREZ, W. C. (1947), Gastroenterology, 9, 754.
3. ALVAREZ, W. C., and MASON, A. Y. (1940), Proc. Staff Meet. Mayo Clin., I5, 6i6.
4. ATKINSON, M. (1943), Ann. Int. Med., I8, 797.
5. AULD, A. G. (1920), Brit. Med. J., 1, 567.