Stotler, Raymond E.; Barbara J. Candall-Stotler (1977). A checklist of the liverworts and hornworts of North America. The Bryologist (American Bryological and Lichenological Society) 80 (3): 405–428.
JSTOR 3242017.
doi:
10.2307/3242017. ↑ Duff, R. Joel; Juan Carlos Villarreal, D. Christine Cargill, & Karen S. Renzaglia (2007). Progress and challenges toward a phylogeny and classification of the hornworts. The Bryologist 110 (2): 214–243.
doi:
10.1639/0007-2745(2007)110[214:PACTDA]2.0.CO;2. Villareal, J. C.; Cargill, D. C.; Hagborg, A.; Söderström, L.; Renzaglia, K. S.
A synthesis of hornwort diversity: Patterns, causes and future work (pdf). Phytotaxa 9: 150–166.
