Bell, N. E.; Hyvonen, J. (2010), «A phylogenetic circumscription of Polytrichastrum (Polytrichaceae): Reassessment of sporophyte morphology supports molecular phylogeny», American Journal of Botany97 (4): 566-78, PMID21622419, doi:10.3732/ajb.0900161.
Bell, NE; Hyvönen, J (2010), «Phylogeny of the moss class Polytrichopsida (BRYOPHYTA): Generic-level structure and incongruent gene trees», Molecular Phylogenetics & Evolution55 (2): 381-98, PMID20152915, doi:10.1016/j.ympev.2010.02.004.
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Bell, N. E.; Hyvonen, J. (2010), «A phylogenetic circumscription of Polytrichastrum (Polytrichaceae): Reassessment of sporophyte morphology supports molecular phylogeny», American Journal of Botany97 (4): 566-78, PMID21622419, doi:10.3732/ajb.0900161.
Bell, NE; Hyvönen, J (2010), «Phylogeny of the moss class Polytrichopsida (BRYOPHYTA): Generic-level structure and incongruent gene trees», Molecular Phylogenetics & Evolution55 (2): 381-98, PMID20152915, doi:10.1016/j.ympev.2010.02.004.