1. S. Achiwa,Shiga-Kenritsu Tanki Darguku Grakujutsu Zasshi (Japan) 16 (1975) 7.
2. Idem, ibid. 16 (1975) 12.
3. T-S. Huang,Hua-Hsueh 4 (1974) 114.
4. E. Villarrea-Idominguez, British patent 1,491,888 16 Nov. 1977.
5. K. V. Kotdesch (ed.) ?Batteries? Vol. 2, Marcel Dekker, New York (1977).