1. Gol’danskii, V.I. and Kuz’min, V.V., Usp. Fiz. Nauk, 1989, vol. 157, no. 1, p.3.
2. Safronov, V.S., Evolution of the Protoplanetary Cloud and Formation of the Earth and the Planets (NASA TTF 677), Jerusalem: Israel Program of Scientific Translations, 1972.
3. Butlerov, A.M., Sochineniya, vol. 1: K istorii proizvodnykh metilena, (Set of Works, vol. 1: On the History of Methylene Production), Moscow: Izd. AN SSSR, 1953, p.63.
4. Khomenko, T.I., Sakharov, M.M., and Golovina, O.A., Usp. Khim., 1980, vol. 49, p. 1079.
5. Pestunova, O.P., Simonov, A.N., Snytnikov, V.N., and Parmon, V.N., Biosphere Origin and Evolution, Dobretsov, N., Kolchanov, N., Rozanov A., and Zavarzin, G., Eds., New York: Springer, 2008, p.103.