Skrypnik, W. I. “Equilibrium in Quantum Systems of Particles With Magnetic Interaction. Fermi and Bose Statistics”. Ukrains’kyi Matematychnyi Zhurnal, vol. 49, no. 5, May 1997, pp. 691–698, https://umj.imath.kiev.ua/index.php/umj/article/view/5050.