1. US Patent 4 230 545 (1980).
2. A. P. Tomilov and N. E. Chomatov in ?Encyclopedia of the Electrochemistry of Elements? Vol. 2 (edited by A. J. Bard), Marcel Dekker, New York (1973) p. 23.
3. F. Beck in ?The Electrochemistry of Lead? (edited by A. T. Kuhn), Academic Press, London (1979) p. 74.
4. C. I. Bushrod and N. A. Hampson,Trans. Inst. Metal Finish 48 (1970) 131.
5. J. L. Dawson in ?The Electrochemistry of Lead? (edited by A. T. Kuhn), Academic Press, London (1979) p. 327.