Links
Cycadophyta
Stevenson, D. W. (1992): A Formal Classification of the Extant Cycads. [s.l.]
Brittonia Vol. 44, no.2, p. 220-23 Lilí Martínez-Domínguez, Fernando Nicolalde-Morejón, Marlon Aramis González-Aguilar, Francisco Vergara-Silva and Dennis Wm. Stevenson (2024): Ceratozamia gigantea (Zamiaceae), A New Species of Cycad, endemic to the mountain Karst Forests of Tabasco, Mexico: what the reproductive structures revealed
Kew Bulletin https://link.springer.com/article/10.100...
Vytopil J.: Haynes, J. L. (2006): Historical Review of the World List of Cycads
Unpublished. 37 pp. http://www.iucn.org/themes/ssc/sgs/csg/publicat...
Kvaček, J. (2008): New cycad foliage of Pseudoctenis babinensis from the Bohemian Cenomanian
Acta Mus. Nat. Pragae, Ser. B, Hist.Nat., 64(2–4): 125–131 Hill K. D., Stevenson D. W., Osborne R. (2004): The world list of cycads
Pp. 195-212, In: J.A. Lindström (ed.), Proceedings of the Sixth International Conference on Cycad Biology (CYCAD 2002). Nong Nooch Tropical Garden, Pattaya, Thailand. http://www.iucn.org/themes/ssc/sgs/csg/publicat...