Zorii, N. V. “Extremal Problems in the Theory of Capacities of Condensers in Locally Compact Spaces. II”.
Ukrains’kyi Matematychnyi Zhurnal
, vol. 53, no. 4, Apr. 2001, pp. 466-88,
https://umj.imath.kiev.ua/index.php/umj/article/view/4269
.