Skrypnik, W. I. “Periodic Coulomb Dynamics of Two Equal Negative Charges in the Field of Four Equal Positive Fixed Charges”. Ukrains’kyi Matematychnyi Zhurnal 72, no. 10 (October 25, 2020): 1432–1442. Accessed April 26, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/741.