Petrila, T., and M. Kohr. “ Some Boundary Element Techniques for Stokes Flows (Part I)”. Rev. Anal. Numér. Théor. Approx., vol. 21, no. 2, Aug. 1992, pp. 167-82, https://ictp.acad.ro/jnaat/journal/article/view/1992-vol21-no2-art9.