P. S. Dabeer and  G. K. Purohit,  Determination of Surface Roughness by Ball Burnishing Process Using Factorial Techniques.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    July 2013, vol. 79(7). 1528 - 1531
    [viewed 20 October 2019]. Available from: https://publications.waset.org/pdf/16441.