@article{VaYoLeMa2011,
	author={J. Vankerschaver and H. Yoshimura and M. Leok and {J. E.} 
Marsden},
	title={The {H}amilton--{P}ontryagin Principle and Multi-{D}irac 
Structures for Classical Field Theories},
	journal={Journal of Mathematical Physics},
	note={(submitted)},
	year={2011},
}