M. A. B. Sidik, D. Amalia, T. E. Agustina, N. F. P. Dinata, S. Fitria, and W. A. O. Anwar, “Development of insulation oil based on Palm Oil Mill Effluent with nano silica”, Sinergi, vol. 28, no. 2, pp. 395–404, May 2024.