Hamad K. Al-Khalid and  Ayman M. Alaskari and  Samy E. Oraby,  Hardness Variations as Affected by Bar Diameter of AISI 4140 Steel.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2011, vol. 51(3). 609 - 615
    [viewed 25 April 2024]. Available from: https://publications.waset.org/pdf/9476.