Pteridologie
- Hortus Botanicus Leiden [nl]
- Kathleen M. Pryer’s Lab / Duke University, Durham, North Carolina [us]
- Leptosporangiate Ferns Kathleen M. Pryer and Alan R. Smith [us]
- Phyto Images Southern Illinois University Carbondale, Illinois [us]
- Ecology & Evolutionary Biology / EEB University of Connecticut, Storrs [us]
- Pteridología en el Instituto de Ecología, A.C, Xalapa, Veracruz [mx]
- Ferns of the Canberra Region.
- Ferns and Lycophytes of the World.
