1. C. Hansch and E. W. Deutch, J. Med. Chem.,8, 705–706 (1965).
2. E. F. Panarin, M. V. Solovskii, and V. A. Kropachev, in: Semisynthetic Penicillins [in Russian], Moscow (1969), pp. 58–63.
3. E. F. Panarin and M. V. Solovskii, Antibiotiki, No. 10, 882–885 (1971).
4. I. T. Strukov, Antibiotiki, No. 11, 963–976 (1963).
5. R. H. Depue, A. G. Moat, and A. Bondi, Arch. Biochem.,107, 374–381 (1964).