Xu, J.- jun, Xu, Y.- chao, Yan, L.- mei, Zhao, H.- long, Sun, Z.- gang, Bai, L.- li, & Xie, M.- xia. (2013). Research on the method of optimal PMU placement. International Journal of Online and Biomedical Engineering (iJOE), 9(S7), pp. 24–29. https://doi.org/10.3991/ijoe.v9iS7.3189