Komarov,N.V. et al.
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1971 , vol. 20, p. 790 - 791
Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1971 , vol. 20, # 4 p. 872 - 873

Crossley, Roger; Shepherd, Robin G.
Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1985 , p. 1917 - 1920