Villarreal, J. C., D. C. Cargill, A. Hagborg, L. Söderström, e K. S. Renzaglia (2010). "A synthesis of hornwort diversity: Patterns, causes and future work". Phytotaxa9: 150–166. doi:10.11646/phytotaxa.9.1.8.
Renzaglia, K., Villarreal, J., & Duff, R. (2008). "New insights into morphology, anatomy, and systematics of hornworts.". En B. Goffinet (Autor) & A. Shaw (Edición) - Cambridge: Cambridge University Press. Bryophyte Biology. pp. 139–172. doi:10.1017/CBO9780511754807.004.
D. Christine Cargill, Karen S. Renzaglia, Juan Carlos Villarreal, and R. Joel Duff (2005). "Generic concepts within hornworts: Historical review, contemporary insights and future directions". Australian Systematic Botany18: 7–16. doi:10.1071/sb04012.