1. L. Tschugaeff, B.,35, 3912 (1902).
2. Th. Zerewitinoff, B.40, 2023 (1907),41, 2233 (1908),42, 4802 (1909),43, 3590 (1910),47, 1659 (1914), 2417 (1914),B. Oddo, B.44, 2048 (1911).
3. H. Hibbert undJ. J. Sudborough, Proc.,19, 285 (1903),20, 165 (1904).
4. J. Meisenheimer, B.61, 708 (1928);
5. J. Meisenheimer undW. Schlichtenmayer, B.61, 2029 (1928).