1. Sugano, Taihei, (Ed.), Design, manufacture, and testing methods of springs. Nikkan Kogyo Shimbunsha: Japan Society for Spring Research; 2001 [in Japanese].
2. Mechanical springs;Wahl,1984
3. M. Shimozaki, FEM for springs. Nikkan Kogyo Shimbunsha, Japan Society of Spring Engineers; 1997 [in Japanese].
4. The effect of residual stress on fatigue crack propagation;Prawoto;J Pract Fail Anal, ASM Int,2002
5. HKDH, Badhesia. Bainite in steels. The Institute of Materials; 1992.