Führer, T., Melenk, J. M., Praetorius, D., & Rieder, A. (2015). Optimal additive Schwarz methods for the hp-BEM: the hypersingular integral operator in 3D on locally refined meshes. Computers and Mathematics with Applications, 70(7), 1583–1605. https://doi.org/10.1016/j.camwa.2015.06.025