@article {798,
	title = {Die Hummeln als G{\"a}ste der Blattl{\"a}use. },
	journal = {Ann. Soc. Zool.-Bot. Fenn. Vanamo},
	volume = {8},
	year = {1929},
	pages = {51-52},
	author = {Hulkkonen, O.}
}
@article {797,
	title = {Zur Biologie der s{\"u}dfinnischen Hummeln},
	journal = {Ann. Univ. Aboensis A},
	volume = {3},
	year = {1928},
	pages = {1-81},
	author = {Hulkkonen, O.}
}
@article {796,
	title = {Kimalaiset lehtikirvojen vieraina. },
	volume = {31},
	year = {1927},
	pages = {216-?},
	author = {Hulkkonen, O.}
}
