@article {Percival1992,
	title = {The effect of winter grazing by barnacle geese on grassland yields on Islay},
	journal = {Journal of Applied Ecology},
	volume = {29},
	number = {1},
	year = {1992},
	pages = {35{\textendash}40},
	publisher = {British Ecological Society},
	url = {http://www.jstor.org/stable/2404344},
	author = {Percival, SM and Houston, DC}
}
