4) Ras, G. J., Anderson, R., Eftychis, H. A., Koch, U., Theron, A., Vanwyk, H. A. & Olivier, L. R.: Chemoprophylaxis with erythromycin stearate or amoxycillin in patients with chronic bronchitis-Effects on cellular and humoral immune functions. Sa. Med. J., 66: 955-958, 1984.
5) Knowles, G. K., Milton, A. F., Fawcett, I. W. & Davies, R. J.: A preliminary comparison of erythromycin, co-trimoxazole, and amoxycillin in patients with acute exacerbations of chronic bronchitis admitted to hospital. J. Int. Med. Res., 8 (Suppl. 2): 51-58, 1980.