1. E. Kabo and A. Ekberg: Wear, 2002, vol. 253, pp. 26–34.
2. A. Ekberg and E. Kabo: Wear, 2005, vol. 258, pp. 1288–1300.
3. K. Handa, Y. Kimura, and Y. Mishima: Proc. Materials Science and Technology (MS&T) 2008, Pittsburgh, PA, Oct. 5–9, 2008, The Printing House, Inc., Stoughton, WI, pp. 2001–09.
4. Japanese Standards Association: JIS E 5401-1, JSA, Tokyo, Japan, 1998.
5. International Union of Railways: UIC CODE 541-3, 5th ed., UIC, Paris, France, 2004.