1. W. Manchot, Liebigs. Ann. Chem.417, 93 (1918).
2. A. N. Nesmeyanov, I. F. Lutsenko, and N. N. Vereshchagina, Izvest.Akad.Nauk SSSR, OtdeLKhim. Nauk 63 (1947).
3. K. Auwers and W. Roth, Liebigs, Ann. Chem.373, 245 (1910).
4. H. Stobbe and O. Zeitschel, Ber.34, 1966 (1901).
5. O. Dimroth, Ber.35, 2853 (1902).