1. G. A. Aksel'rud, Ya. M. Gumnitskii, and I. N. Fiklistov, Inzh.-Fiz. Zh.,17, No.4 (1969).
2. G. A. Aksel'rud, Theory of Diffusion Extraction of Substances from Porous Bodes [in Russian], Izd. Politekhnicheskogo Instituta, L'vov (1959).
3. F. Helferick, Ionites. Principles of Ion Exchange [Russian translation], IL (1962).
4. G. A. Aksel'rud, Zh. Fiz. Khim.,37, 1251 (1963).