Elets, L.V. and Masharov, P.A. (2009) “On one extremal problem of Pompeiu sets”, Ukrains’kyi Matematychnyi Zhurnal, 61(1), pp. 61–72. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/3001 (Accessed: 26 April 2025).