MoskovitsM. and OzinG. A., Appl. Spectrosc.26, 481 (1972).
3.
Type EX crystal, available from 3 to 60 MHz from International Crystal Mfg. Co., 10 North Lee, Oklahoma City, Okla. 73102 ($3.95). A suitable oscillator circuit and power supply with case is available from the same manufacturer for $20.50 (case FOT-10 with oscillator OT-3).
4.
WarnerA. W., in Ultra Micro Weight Determinations, WolskyS. P. and ZdanukE. J., Eds. (Wiley, New York, 1969), Chap. 7.