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Albach & Meudt, D.C. & H.M. (2010). "Phylogeny of Veronica in the Southern and Northern Hemispheres based on plastid, nuclear ribosomal and nuclear low-copy DNA". Molecular Phylogenetics and Evolution. 54 (2): 457–471. doi:10.1016/j.ympev.2009.09.030. PMID19796701.
Albach & Meudt, D.C. & H.M. (2010). "Phylogeny of Veronica in the Southern and Northern Hemispheres based on plastid, nuclear ribosomal and nuclear low-copy DNA". Molecular Phylogenetics and Evolution. 54 (2): 457–471. doi:10.1016/j.ympev.2009.09.030. PMID19796701.