W. I. Skrypnik, “Equilibrium in quantum systems of particles with magnetic interaction”, Ukr. Mat. Zhurn., vol. 47, no. 12, pp. 1686–1691, Dec. 1995, Accessed: Apr. 07, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5562