Stanich, Nicholas; Gar W. Rothwell; Ruth A. Stockey (2009). "Phylogenetic diversification of Equisetum (Equisetales) inferrred from Lower Cretaceous species of British Columbia, Canada". American Journal of Botany. 96 (7): 1289–1299. doi:10.3732/ajb.0800381. PMID21628278.
Stanich, Nicholas; Gar W. Rothwell; Ruth A. Stockey (2009). "Phylogenetic diversification of Equisetum (Equisetales) inferrred from Lower Cretaceous species of British Columbia, Canada". American Journal of Botany. 96 (7): 1289–1299. doi:10.3732/ajb.0800381. PMID21628278.