Le, P., D. Hoang, H. Pham, and H. Nguyen. “New Adaptive Droop Control With Combined Line Impedance Estimation Method for Parallel Inverters”. VNUHCM Journal of Science and Technology Development, Vol. 19, no. 4, Dec. 2016, pp. 45-64, doi:https://doi.org/10.32508/stdj.v19i4.781.