1. B. Pekić, “Hemija i tehnologija farmaceutskih proizvoda-Alkaloidi i etarska ulja” (Chemistry and Technology of Pharmaceutical Products-Alkaloids and Essential Oil), Faculty of Technology, University of Novi Sad, 1983.
2. C. F. Emanuel, M. V. Emanuel, U. S. Pat. 4,007,186 (1977).
3. J. Duoros, I. T. Warder, U. S. Pat. 3,850,930 (1974) and 4,045,582 (1977).
4. K. Suzuki, A. Nishizaki, Bull. Agr. Chem. Soc. Japan,7, 59 (1931); C. A.26, 43526 (1932).
5. R. Yarchoan, S. Broder, N. Engl. J. Med.,316, 557 (1987).