Akram Hussein, Haidar, et al. “TRIBOLOGICAL BEHAVIOR AND LUBRICATION MECHANISM OF FINE PARTICLES IN THE BASE OIL SN500”. Journal of Engineering and Sustainable Development, vol. 23, no. 5, Sept. 2019, pp. 108-16, https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/207.