Babanin, Oleksandr, et al. “Application of Synthetic Filters from Polypropylene in Diesel Locomotive Oil Systems to Improve the Efficiency of Cleaning Engine Oil”. International Journal of Engineering & Technology, vol. 7, no. 4.3, Sept. 2018, pp. 162-6, https://doi.org/10.14419/ijet.v7i4.3.19728.