Pasynkova, I. A. “Cylindrical Precessions of an Unbalanced Jeffcott Rotor With Four Degrees of Freedom in Non-Linear Elastic Supports”. Technische Mechanik - European Journal of Engineering Mechanics, vol. 26, no. 2, Aug. 2019, pp. 117-30, https://journals.ub.ovgu.de/index.php/techmech/article/view/881.