Xue Jiang & Xujing Li. (2019). Perfectly Matched Layer Method for Acoustic Scattering Problem by a Locally Perturbed Line with Impedance Boundary Condition.
            <i>Advances in Applied Mathematics and Mechanics</i>. <i>12</i> (1).
            101-140.
         doi:10.4208/aamm.OA-2019-0047