1. V. M. Berezovskii, Chemistry of Vitamins [in Russian], Moscow (1973), pp. 34–46.
2. V. A. Devyatnin, V. M. Svetlaeva, L. O. Shnaidman, and L. M. Baigel'man, Khim.-farm. Zh., No. 5, 39–42 (1967).
3. V. M. Svetlaeva, N. A. Shikhaleva, and L. A. Poteeva, Khim.-farm. Zh., No. 2, 52–56 (1973).
4. V. M. Svetlaeva, L. G. Kuznetsova, and M. P. Mogilevskaya, Zh. Anal. Khim.,28, No. 7, 1427–1429 (1973).
5. M. Ts. Yanotovskii and A. B. Shawich, Khim.-farm. Zh., No. 11, 1287–1292 (1985).