1. L. da Vinci, Treaty of statics and mechanics, Codex Madrid 1(1493), 8937.
2. History of Tribology;Dowson,1998
3. Materials and Surface Engineering in Tribology;Takadoum,2008
4. Nanotribology and Nanomechanics–An Introduction;Bhushan,2008
5. Electric Contacts: Theory and Application;Holm,1967