1. M. Shipchandler and T. O. Soine, J. Pharm. Sic.,57, 2062 (1968).
2. L. G. Avramenko, G. K. Nikonov, and M. G. Pimenov, Khim. Prirodn. Soedin., 190 (1968).
3. A. I. Sokolova and G. K. Nikonov, Khim, Prirodn. Soedin., 318 (1969).
4. G. P. Shavora and A. D. Turova, Second Symposium on the Study of Natural Coumarins (Abstracts of Lectures) [In Russian], Leningrad (1970), p. 8].
5. R. G. Cooks and D. H. Williams, Chem, Commun., 663 (1968).