1. Adderson, J. E., W. C.Evansand G. E.Trease: J. Pharm.13, 224–239 (1961).
2. Atkinson, L. R.: Phytomorphology10, 26–36 (1960).
3. Baillaud, L., et Y.Courtot: Ann. Sci. Univ. Besançon, Bot., Sér.2, 15, 59–64 (1960).
4. Balfour, E. E., and W. R.Philipson: Phytomorphology12, 110–143 (1962).
5. Ball, E.: Phytomorphology10, 377–396 (1960).