PrykarpatskyA. K., SamoilenkoV. G., and TaneriU. “The Reduction Method in the Theory of Lie-Algebraically Integrable Oscillatory Hamiltonian Systems”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 55, no. 2, Feb. 2003, pp. 232-40, https://umj.imath.kiev.ua/index.php/umj/article/view/3901.