@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	address = {unpublished keys},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 {565,
	title = {Identification key of Siberian species (Orthoneura)},
	journal = {(Russian)},
	year = {1979},
	pages = {49-56},
	keywords = {Key to species, Orthoneura, Orthonevra, Palaearctic, Syrphidae},
	author = {Violovitsh, N.A.}
}
@article {462,
	title = {<i>Brachyopa obscura</i> Thompson \& Torp, 1982 - neu f{\"u}r Deutschland (Diptera: Syrphidae)},
	journal = {Studia dipterologica},
	volume = {8},
	number = {1},
	year = {2001},
	pages = {257-260},
	keywords = {Brachyopa, diagnostic characters, faunistics, new record, Palaearctic, Syrphidae, vulnerability},
	author = {Stuke, Jens-Hermann}
}
