@article {2495,
	title = {Systematics of the Usnea fragilescens aggregate and its distribution in Scandinavia},
	journal = {Nordic Journal of Botany},
	volume = {7},
	year = {1987},
	pages = {479-495},
	issn = {0107055X},
	doi = {10.1111/njb.1987.7.issue-410.1111/j.1756-1051.1987.tb00969.x},
	author = {Clerc, P.}
}
@article {2483,
	title = {Key to European Usnea species},
	journal = {Bibliotheca Lichenologica},
	volume = {100},
	year = {2009},
	pages = {419-462},
	url = {http://home.comcast.net/~nwlichens/Randlane_et\%20al_2009Usnea.pdf},
	author = {Randlane, T. and T{\~o}rra, T. and Saag, A. and Saag, L.}
}
@inbook {2472,
	title = {Usnea},
	booktitle = {Lichens of Great Britain and Ireland},
	year = {2009},
	publisher = {British Lichen Society},
	organization = {British Lichen Society},
	address = {London},
	author = {James, P.W. and Clerc, P. and Purvis, O.W.}
}
