1. ”Quartz for the national defense stockpile,” NMAB-424, National Academy Press, Washington, DC (1985).
2. ”NDK Quartz,” C-12B17 1000D, Nihon Dempa Kogyo Co Ltd, July (1981).
3. ”Guide for the use of quartz crystal units for frequency control and selection,” IS: 2935-1980, Indian Standards Institution, January (1981).