1. Recent developments in methods for the esterification and protection of the carboxyl group
2. Wünsch, E. 1974.Methoden der Organischen ChemicEdited by: Houben, Weyl. Vol. 15, 358 a, vol. part 1, p., Georg Thieme Stuttgart
3. Roeske, R. W. 1981.The PeptidesEdited by: Gross, E. and Meienhofer, J. Vol. 3, 116 p., Acad. Press New York
4. Pless, J., Guttmann, S. and Beyermann, H-C., eds. 1966.Peptides50 et al., North Holland Amsterdam,1967
5. Chemistry of cephalosporin antibiotics. 30. 3-Methoxy- and 3-halo-3-cephems