References
- Penicillins and Cephalosporins. Their Chemistry and Biology E. H. Flynn
- Amino Acids, Peptides and Related Compounds. H. A. James
- Nature v.248 A. M. Altschul
- J. Heter. Chem. v.7 D. Ben-Ishai;G. Ben-Et;A. Warshawsky
- Tetrahedron v.31 U. Zoller;D. Ben-Ishai
- Synthesis H. E. Zaugg;W. B. Martin