@article {675,
	title = {Acidification and Otter (Lutra-Lutra) Distribution in Scotland},
	volume = {43},
	year = {1989},
	pages = {365-374},
	author = {Mason, C.F. and Macdonald, S.M.}
}
@article {677,
	title = {Acidification and otter Lutra lutra distribution on a British river. },
	volume = {51},
	year = {1987},
	pages = {81-87},
	author = {Mason, C.F. and Macdonald, S.M.}
}
