title: The concurrence of two species of nematodes of the genus Heligmosomum in a field-vole (Microtus arvalis) population in large-acreage lucerne fields.
mesh_terms: D000818:Animals; D004463:Ecology; D009348:Nematoda / Q000254:growth & development; D011044:Poland; D012377:Rodentia / Q000469:parasitology*; D012621:Seasons