AHMAD, Mahmood et al. Large Banks of Negative Differential Resistance Nonlinear Loads: A Hidden Threat to Power System Quality. Mehran University Research Journal of Engineering and Technology, [S.l.], v. 37, n. 1, p. 8, jan. 2018. ISSN 2413-7219. Available at: <https://publications.muet.edu.pk/index.php/muetrj/article/view/101>. Date accessed: 05 mar. 2021. doi: http://dx.doi.org/10.22581/muet1982.1801.06.