Lewis, Louise A.; Richard M. McCourt:. Green algae and the origin of land plants. American Journal of Botany 2004: 91 (10): 1535–1556. http://dx.doi.org/10.3732/ajb.91.10.1535
Smith, Alan R., Kathleen M. Pryer, E. Schuettpelz, P. Korall, H. Schneider, & Paul G. Wolf. (2006). "A classification for extant ferns". Taxon 55(3): 705–731 http://www.pryerlab.net/publication/fichier749.pdf