Watson, J. M., and A. R. FLORES. “Upping Their Number, Addressing Their Risk. <em>Viola singularis</em> (Violaceae) Revisited, and an Evaluation of Sect. <em>Andinium</Em>, Its Higher Taxonomic Group”. Phytotaxa, vol. 177, no. 3, Aug. 2014, pp. 177–182, doi:10.11646/phytotaxa.177.3.6.