1. Monographs and comprehensive reviews:
2. J. H. Lister in:The Chemistry of Heterocyclic Coumpounds(Eds.: A. Weissberger E. C. Taylor) Wiley Interscience 1971 vol. 24 whole book.
3. G. Shaw in:Comprehensive Heterocyclic Chemistry(Eds.: A. R. Katritzky C. W. Rees) Pergamon Press 1984 vol. 5 pp. 501−597.
4. D. F. Ewing G. Mackenzie in:Second Supplements to the 2nd Edition of Rodd’s Chemistry of Carbon Compounds vol. IV K(partial)/L (Ed.: M. Sainsbury) Elsevier Science B. V. 1999 pp. 127−179.
5.