1. Bijdrage tot de kennis der West-Indische Volksgeneeskruiden, p. 108, Ph.D. Thesis, State University of Utrecht, The Netherlands (1930).
2. Atlas of Medicinal Plants of Middle America — Bahamas to Yucatan, p. 761, Charles C. Thomas, Springfield, IL (1981).
3. and , Die ätherischen Öle, 4th edn, Vol. VII, p. 472, Akademie-Verlag, Berlin (1961).
4. Essential Oils of Some Amazonian Labiatae, I: Genus Hyptis