Spaeth; Wessely
Monatshefte fuer Chemie, 1928 , vol. 49, p. 235

Kirillova, K. M.; Skvortsova, T. A.; Nikonova, L. Z.; Chugunov, Yu. V.; Igonin, V. B.; Mukhtarov, A. Sh.
Journal of Organic Chemistry USSR (English Translation), 1992 , vol. 28, # 3.1 p. 427 - 430
Zhurnal Organicheskoi Khimii, 1992 , vol. 28, # 3 p. 527 - 530

Will; Albrecht
Chemische Berichte, 1884 , vol. 17, p. 2103

Will
Chemische Berichte, 1888 , vol. 21, p. 615