@article {VanDerVliet1991,
	title = {{\emph{Microtus-Oeconomus} and \emph{Microtus-Agrestis} on the Island of Texel}},
	journal = {Lutra},
	volume = {34},
	number = {2},
	year = {1991},
	pages = {53-39},
	author = {{Van Der Vliet}, F. and Nieuwenhuizen, W.}
}