References

1. Antibiotics, Research and Development of Penicillins and Cephalosporins Y.M. Goo
2. Special Publication No 28 Recent Advances in the Chemistry of ${\beta}$-Lactam Antibiotics R.B. Woodward;J. Elks(Ed.)
3. J. Am. Chem. Soc. v.101 H.R. Pfaendler;J. Gosteli;R.B. Woodward
4. J. Antibiot. v.32 J.S. Kahan;F.M. Kahan;R.Goegelman;S.A.Currie;M. Jackson;E.O. Stapley;T.W. Miller;A.K. Miller;D. Hendlins;S. Mochles;S. Hernandez;H.B. Woodreff;J. Birnbaum
5. Chemistry and Biology of ${\beta}$-Lactam Antibiotics v.2 R.W. Ratcliffe;G. Albers-Schonberg;R.B. Morin(Ed.);M. Gorman(Ed.)
6. Antibiotics, Research and Development of Penicillins and Cephalosporins Y.M. Goo
7. J. Chem. Soc. Chem. Commun. E.G. Brain;A.J. Eglington;J.H.C. Nayler;M.J. Person;R. Southgate
8. Helv. Chim. Acta. v.55 K. Heusler
9. J. Am. Chem. Soc. v.95 J.C. Sheehan;D. Ben-Ishai;J.V. Piper
10. Tetrahedron Lett. S. Wolfe;M.R. Goeldner
11. J. Chem. Soc., Perkin Trans I R.J. Stoodley;N.R. Whitehouse
12. J. Chem. Soc., Perkin Trans I E.G. Brain;A.J. Eglington;J.H.C. Nayler;M.J. Pearson;R. Southgate
13. Chemistry and Biology of ${\beta}$-Lactam Antibiotics v.2 I. Ernest
14. Antibiotics, Research and Development of Penicillins and Cephalosporins Y.M. Goo