@article {59,
	title = { Zoogeography of Bombus and Psithyrus in north-western Europe (Hymenoptera, Apidae).},
	journal = {Annales Zoologici Fennici},
	volume = {30},
	year = {1993},
	pages = {187-208},
	keywords = {Aculeata, Apidae, Bombus},
	author = {Pekkarinen, A. and Ter{\"a}s, I.}
}
@article {48,
	title = { Flower visits of bumblebees, Bombus Latr. Hymenoptera, Apidae), during one summer},
	journal = {Annales Zoologici Fennici},
	volume = {13},
	year = {1976},
	pages = {200-232},
	keywords = {Aculeata, Bombus},
	author = {Ter{\"a}s, I.}
}
