APA (7th ed.) Zitazioa
Christensen, T. G. (1990). An African tree of life. Orbis Books.
Chicago Style (17th ed.) Zitazioa
Christensen, Thomas G. An African Tree of Life. Maryknoll, N.Y.: Orbis Books, 1990.
MLA (9th ed.) Zitazioa
Christensen, Thomas G. An African Tree of Life. Orbis Books, 1990.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.