PROF. MANGRULKAR KAUSTUBH.S., and GADE RAMESHWAR P. “ANALYSIS AND OPTIMIZATION OF BALL BEARINGS FOR ROBOTS TO INCREASES EFFICIENCY, ALSO REDUCE STRESS”. International Journal of Innovations in Engineering Research and Technology, vol. 6, no. 6, Mar. 2021, pp. 1-8, https://repo.ijiert.org/index.php/ijiert/article/view/1845.