@article {Graaf,
	title = {Sward height and bite size affect the functional response of barnacle geese Branta leucopsis},
	journal = {Journal of Ornithology},
	year = {2006},
	pages = {65{\textendash}74},
	url = {http://scholar.google.com/scholar?hl=en\&btnG=Search\&q=intitle:Chapter+4\#1 http://link.springer.com/article/10.1007/s10336-005-0041-5},
	author = {van der Graaf, AJ and Coehoorn, P and Stahl, J}
}
