1. H. Zijlstra,Experimental Methods in Magnetism, (North-Holland, Amsterdam, 1967), Pt. 2, p. 94.
2. Statham UC2 Universal Transducing Cell, Gould Inc., Measurements Systems Division, 2230 Statham Blvd., Oxnard, CA 93030.
3. Calex Multiplier model 602, Calex Mfg. Co., Inc., 3355 Vincent Rd., Pleasant Hill, CA 94523.