References
- Kiwai , M. M. , Khan , N. H. and Ali , M. 1979 . Synth. Commun. , 9 : 363
- 1949 . “ For cyclization of α-acylamino acids by treatment with phosphorous halides compare e.g. J.W. Cornforth ” . In The Chemistry of Penicillin , 730 Princeton : Princeton Univ. Press .