1. NMR was reviewed, e.g., by G.Laukien: In:Handbuch der Physik, Vol. 38/1, Ed. by S. Flügge (Springer-Verlag, Berlin, Göttingen, Heidelberg, 1958); a typical magnetometer was described, e.g., by H. Winterhoff: AEG Mitteilungen53, 277 (1963)
2. S.Wilking: Z. Phys.157, 401 (1959)
3. J.R.Tatarczuk, B.Ziegler: Nucl. Instr. Meth.41, 45 (1966)
4. Varian Ass.: Data sheet V 4970, V 4937 A
5. R.Miguel: Rev. Phys. Appl.5, 135 (1970)