Fig. 1, the hysteresis loop: any textbook on electrical, engineering, e.g. p. 182, Principles of Electrical Engineering by T. F. Wall, Chemical Publ. Co., Brooklyn, N.Y. (1947)
2.
Figs. 2 & 3, the transformed null curve: based on B–H data appearing in the International Critical Tables under the subject of magnetism
3.
The function exp — (1/|Pi(x)|): introduced by the author of this article, p. 679, Biometrics (Dec. 1963)
