5Yan M F. Study on absorption and transport of carbon in steel during gas carburizing with rare earth addition Mater Chem Phy, 2001 ;70 (2) :242-245.
6Benedetti M. Influence of shot peening on bending tooth fatigue limit of case hardened gears. Interational Journal of Fatigue, 2002; 24 (50) : 1127-1136.