1. D. E. Hughes, Induction Balance and Experimental Researches Therewith, Phil. Mag., 8:50 (1879).
2. W. Lord and D. J. Oswald, Leakage Field Methods of Defect Detection, Int. J. NDT, 4:249 (1972).
3. R. C. McMaster, “Nondestructive Testing Handbook,” Vol. II, ASNT, Columbus (1959).
4. W. J. McGonnagle, “Nondestructive Testing,” Gordon and Breach, New York (1961).
5. J. Lankford and P. H. Francis, Magnetic Field Perturbation Due to Metallurgical Defects, Int. J. NDT, 3:77 (1971).