@article {2499,
	title = {The lichen genus Usnea (lichenized Ascomycetes, Parmeliaceae) in Estonia with a key to the species in the Baltic countries},
	journal = {Lichenologist},
	volume = {39},
	year = {2007},
	pages = {415-438},
	issn = {0024-2829},
	doi = {10.1017/S0024282907007220},
	author = {T{\~o}rra, T. and Randlane, T.}
}
@article {2474,
	title = {Phylogenetic relations of European shrubby taxa of the genus Usnea},
	journal = {Lichenologist},
	volume = {43},
	year = {2011},
	pages = {427-444},
	issn = {0024-2829},
	doi = {10.1017/S0024282911000375},
	author = {Saag, L. and T{\~o}rra, T. and Saag, A. and Del-Prado, R. and Randlane, T.}
}
