1. Bragg, W. H.: Nature 95, 561 (1915)
2. Spaldin, N.A.: Magnetic materials: fundamentals and device applications, p. 119. Cambridge University Press, United Kingdom, (2003)
3. Jiles, D.C.: Introduction to Magnetism and Magnetic Materials, Chapman and Hall, USA 2nd edn, p. 89 (1998)
4. Cullity, B.D.: Introduction to Magnetic Materials, Wiley-IEEE Press, USA 2nd edn, p. 45 (2011)
5. Spaldin, N.A.: Magnetic Materials Fundamentals and Applications, Cambridge University Press, United Kingdom 2nd edn, p. 14 (2011)