@article {51,
	title = {Distribution of bumble-bees (Hymenoptera, Apidae: Bombus and Psithyrus) in Eastern Fennoscandia.},
	journal = {Notulae Entomologicae},
	volume = {61},
	year = {1981},
	pages = {71-89},
	keywords = {Aculeata, Apidae, Bombus, pdf},
	author = {Pekkarinen, A. and Ter{\"a}s, I. and Viramo, J. and Paatela, J.}
}
@article {50,
	title = {Patterns of resource utilization in two Fennoscandian bumblebee communities},
	journal = {Oikos},
	volume = {36},
	year = {1981},
	pages = {1-11},
	keywords = {Aculeata, Bombus},
	url = {http://www.jstor.org/stable/3544371?seq=1$\#$page_scan_tab_contents},
	author = {Ranta, E. and Lundberg, H. and Ter{\"a}s, I.}
}
