@article{LeZh2011,
	Author={M. Leok and J. Zhang},
	Title={Discrete {H}amiltonian Variational Integrators},
	Journal={IMA Journal of Numerical Analysis},
	volume={31},
	number={4},
	pages={1497--1532},
	Year={2011},
	doi={10.1093/imanum/drq027},
}