1. aMetzger, J. V. In Comprehensive Heterocyclic Chemistry; Katritzky, A. R., Rees, C. W., Eds. Pergamon Press: New York, 1984; Vol. 6, p 235.
2. bDondoni, A.; Merino, P. In Comprehensive Heterocyclic Chemistry II; Katritzky, A. R., Rees, C. W., Scriven, E. F. V., Eds. Pergamon Press: New York, 1996; Vol. 3, p 373.
3. cChen, B.; Heal, W. In Comprehensive Heterocyclic Chemistry III; Katritzky, A. R., Ramsden, C. A., Scriven, E. F. V., Taylor, R. J. K., Eds. Elsevier: Amsterdam, Netherlands, 2008; Vol. 4, p 635.
4. Synthetic Studies of Biologically Active Marine Cyclopeptides
5. eWu, Y.J.; Yang, B. V. In Progress in Heterocyclic Chemistry; Gribble, G. W., Joule, J. A., Eds. Elsevier: Oxford, U.K., 2007; Vol. 18, p 247.