Alexander A. Burov, Vasily I. Nikonov, “Dynamics of a heavy pendulum of variable length with a movable suspension point”, Acta Mech, 2024
Ivan Yu. Polekhin, “A Topological–Analytical Method for Proving Averaging Theorems on an Infinite Time Interval in a Degenerate Case”, Proc. Steklov Inst. Math., 322 (2023), 188–197
R E Grundy, “The behaviour of a forced spherical pendulum operating in a weightless environment”, Quarterly Journal of Mechanics and Applied Mathematics, 76:3 (2023), 349