“Asymptotic Expansions for Eigenfunctions and Eigenvalues of a Steklov Spectral Problem for Thin Perforated Domains With Rapidly Varying Thickness and Different Boundary Dimensions”. Neliniini Kolyvannya, vol. 19, no. 2, June 2016, pp. 253-75, https://twinhead.imath.kiev.ua/index.php/nosc/article/view/829.