Kumbhar, S. V., A. M. Takale, A. H. Badiwale, A. D. Gawali, and B. S. Bhanase. “Design and Development of Helical Compression Spring Stiffness Testing Machine for I.C. Engine Valves With Stepper Motor by Using Computer Control”. Asian Review of Mechanical Engineering, vol. 7, no. 2, Nov. 2018, pp. 42-45, doi:10.51983/arme-2018.7.2.2449.