1. R J. Baczuk and R. J. DuBois, Analyt. Chemistry40, 685 (1968).
2. E. Pungor (Ed.), Ion-Selective Electrodes. Budapest: Akad�miai Kiad�, 1973. p. 225.
3. T. P. Hadjiioannou and E. P. Diamandis, Analyt. Chim. Acta, in the press.
4. P. Spacu and M. Gafiteanu, Analele Univ. C. I. Parhon-Bukuresti, Seria Stintelor Naturii11, 123 (1956); Chem. Abstr.52, 19723 h (1958).
5. P. Spacu and M. Gafiteanu, Analele Univ. C. I. Parhon-Bukuresti, Seria Stintelor Naturii14, 77 (1957); Chem. Abstr.53, 6888 (1959).