^ 1.01.11.21.3Crane, Peter; Kenrick, Paul. Problems in Cladistic Classification: Higher-Level Relationships in Land Plants. Aliso: A Journal of Systematic and Evolutionary Botany. 1997-01-01, 15 (2): 87–104 [2020-10-09]. ISSN 0065-6275. doi:10.5642/aliso.19961502.04. (原始内容于2021-01-16).
^Novíkov & Barabaš-Krasni. Modern plant systematics. Liga-Pres. 2015: 685. ISBN 978-966-397-276-3. doi:10.13140/RG.2.1.4745.6164.
^Anderson, Anderson & Cleal. Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology. Strelitzia (SANBI). 2007, 20: 280. ISBN 978-1-919976-39-6.
^Pelletier. Empire biota: taxonomy and evolution 2nd ed. Lulu.com. 2012: 354. ISBN 978-1329874008.