Seyferth,D. et al.
Journal of the American Chemical Society, 1969 , vol. 91, p. 5027 - 5033

Rudasheskaya, T. Yu.; Nesmeyanova, O. A.
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1983 , vol. 32, # 8 p. 1647 - 1650
Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1983 , # 8 p. 1821 - 1824

Lespieau; Wakeman
Bulletin de la Societe Chimique de France, 1932 , vol. <4> 51, p. 384,393