1. P.R. Stevenson, US Patent no. 5,093,624 (1992).
2. D. Limuti, J.M. Ross, T.L. Churchill, US Patent no. 5,132,626 (1992).
3. J.F. Beutler, B.J. Burreson, W.A. van Schalkwijk, D.F. Flagg, G.A. Kromholtz, J.J. Green, US Patent no. 5,537,042 (1996).
4. E.Y. Weissman, in: K.V. Kordesch (Ed.), Batteries, Vol. 2, Marcel Dekker, New York, 1977 (Chapter 1).
5. D. Pavlov, E. Bashtavelova, V. Iliev, in: Proceedings of a Symposium on Advances in Lead Acid Batteries, The Electrochemical Society, Pennington, NJ, USA, 1984, p. 16.