1. Förster, F.: McMaster, R.C., Nondestructive testing handbook, (Ronald Press, N.Y. 1959),2, Sections 36–42
2. ‘Impedance calculation tables of finite single layer solenoid coil encircling a cylindrical magnetic conductor and their application’, Memorandum of School of Engineering, Okayama University, 1977 p. 17–2611