1. Azorean biodiversity portal;Borges
2. Natural zonal vegetation of the Azores Islands: characterization and potential distribution
3. Contributions to the flora of the Azores, Madeira, P. Santo and the Canary Islands;Hansen;Boletim do Museu Municipal do Funchal,1992
4. World ferns. Synonymic checklist and distribution of ferns and lycophytes of the world. Version 12.5; last update October 14th, 2021;Hassler