1. Perel’man, F.M. and Zvorykin, A.Ya., Kobal’t i nikel’ (Cobalt and Nickel), Moscow: Nauka, 1975.
2. Shchukarev, S.A., Andreev, S.N., and Burkov, K.A., Dokl. Akad. Nauk SSSR, 1962, vol. 44, no. 2, p. 371.
3. Shmidt, V.S., Ekstraktsiya aminami (Extraction with Amines), Moscow: Atomizdat, 1980.
4. Suruku, A., Eyupoglu, V., and Tutkun, O., J. Ind. Eng. Chem., 2012, vol. 18, no. 2, p. 629.
5. Suruku, A., Eyupoglu, V., and Tutkun, O., Desalination, 2010, vol. 250, no. 3, p. 1155.