Daeva, S.G., and A.V. Setukha. 2015. “On the Numerical Solution of the Neumann Boundary Value Problem for the Helmholtz Equation Using the Method of Hypersingular Integral Equations”. Numerical Methods and Programming (Vychislitel’nye Metody I Programmirovanie) 16 (45):421-35. https://doi.org/10.26089/NumMet.v16r340.