Palyutkіn V. G. “Invariant Measure on a Compact Annular Group”. Ukrains’kyi Matematychnyi Zhurnal 18, no. 4 (June 28, 1966): 49–59. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/8312.