1. Burra, L., Zanolin, F.: Chaotic dynamics in a simple class of Hamiltonian systems with applications to a pendulum with variable length. Differ. Integr. Eqn. 22, 927–948 (2009)
2. Meyer, K.R., Hall, G.R.: Introduction To Hamiltonian Dynamical Systems And The
$$n$$
n
-body Problem. Springer, New York (1992)
3. Mathematics in Science and Engineering;C De Coster,2006
4. Applied Mathematical Sciences;J Mawhin,1989
5. Hastings, S.P., McLeod, J.B.: Chaotic motion of a pendulum with oscillatory forcing. Amer. Math. Mon. 100, 563–672 (1993)