Zhang, Jinguo, and Tsing-San Hsu. “Multiple Solutions for a Fractional Laplacian System Involving Critical Sobolev-Hardy Exponents and Homogeneous Term”. Mathematical Modelling and Analysis, vol. 25, no. 1, Jan. 2020, pp. 1-20, https://doi.org/10.3846/mma.2020.7704.