1. A. I. Khol'kin and L. M. Gindin, ?Extraction of certain metals by n-caproic acids from HCl solutions,? Izv. Sib. Otd. Akad. Nauk SSSR, Ser. Khim. Nauk, Issue 1, No. 2, 57?60 (1979).
2. G. K. Schweitzer and L. H. Howe, ?The solvent equilibria of some cobalt(II) chelates,? J. Inorg. Nucl. Chem., 29, No. 8, 2027?2032 (1967).
3. V. M. Byr'ko, G. M. Baevskaya, and É. E. Rakovskii, ?Extraction of iridium hexamethylene-dithiocarbamate,? Vestn. Mosk. Univ., Ser. Khim., No. 5, 567?569 (1972).
4. R. Pietsch and H. Sinic, ?Studies of extractability of metal ions by homologs of aliphatic carboxylic acids,? Anal. Chim. Acta, 49, No. 1, 51?56 (1970).
5. F. Umland, A. Jenssen, D. Thierig, and G. Wünsch, Complexones in Analytical Chemistry [Russian translation], Mir, Moscow (1975).