Koshmanenko, V. D., and M. E. Dudkin. “Nonzero Capacity Sets and Dense Subspaces in Scales of Sobolev Spaces”. Methods of Functional Analysis and Topology 20, no. 3 (September 25, 2014): 213–218. Accessed December 16, 2025. https://zen.imath.kiev.ua/index.php/mfat/article/view/580.