Hauke, R. L. (1967). The Natural History of Equisetum in Costa Rica.
Chicago Style aipamenaHauke, Richard L. The Natural History of Equisetum in Costa Rica. 1967.
MLA aipamenaHauke, Richard L. The Natural History of Equisetum in Costa Rica. 1967.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.