@article {437,
	title = {Keys to Palaearctic Syrphidae (Diptera) for Genera Sphegina, Zelima, Penthesilea, and Neoascia},
	year = {1956},
	pages = {29},
	address = {unpublished keys},
	keywords = {Diptera, Key to species, Neoascia, Palaearctic, Penthesilea, Sphegina, Syrphidae, Zelima},
	author = {Stackelberg, A.A.}
}
@article {588,
	title = {Syrphidae},
	journal = {Agriculture Canada Monograph},
	volume = {28},
	year = {1987},
	pages = {713-743},
	keywords = {Arthropods, Diptera, Insects, Invertebrates, NEARCTIC REGION, Syrphidae, Systematics \& biology},
	author = {Vockeroth, J.R. and Thompson, F. C.}
}
