1. Dey, N.C., Medical Pathology, P. 53, 81, 1967.
2. Dill, J.L., Annals of Otology & Rhinology, 52, 496, 1956.
3. Goyal, R.K., Sarin, J.C. and Narayanan, Ind. J. Otology, 8, 120, 1956.
4. Hara, H.J., Hoyt, R.E. and Levide M.G., Annals of Oto. Rhinology 56, 769, 1947.
5. Mackie, Handbook of Practical Bacteriology P, 190, 1942.