1a) A. Eschemoser, L. Ruzicka, O. Jeger, D. Arigoni, Hely. Chim. Acta, 38, 1890 (1955)
b) G. Stork, A. W. Burgstahler, J. Am. Chem. Soc., 77, 5068 (1955)
2) P. A. Stadler, A. Nechvatal, A. J. Frey, A. E schenmosr, Hely. Chim. Acta, 40, 1373 (1957)
3) A. Eschenmoser, D. Felix, M. Gut, J. Meier, P. Stadler in “Ciba Foundation Symposium on the Biosynthesis of Terpenes and Sterols”, G. E. W. Wolstenholme and M. O'Connor, Ed., J. and A. Churchill, Ltd., London, 1959
4) P. A. Stadler, A. Eschenmoser, H. Schinz, G. Stork, Helv. Chim. Acta, 40, 2191 (1957)