1. I. G. Zoz, N. F. Komissarenko, and N. A. Chernykh, Rast. Res., No. 2, 276 (1967).
2. A. I. Ban'kovskii, F. L. Burmistrov, A. N. Vasina, P. M. Loshkarev, F. A. Satsiperov, and A. D. Turova, Hoary Erysimum [in Russian], Medgiz, Moscow (1953).
3. V. V. Feofilaktov and M. V. Tsarev, Tr. VILAR, No. 10, 44 (1950).
4. V. V. Feofilaktov and P. M. Loshkarev, Dokl. Akad. Nauk SSSR, 94 (1954).
5. I. F. Makarevich, É. P. Kemertelidze, S. G. Kislichenko, V. V. Zatula, A. A. Reznichenko, D. G. Kolesnikov, and I. P. Kovalev, Cardenolides and Bufadienolides [in Russian], Metsniereba, Tbilisi (1975).