Cita APA (7th ed.)
Friedrich, P. (1970). Proto-indo-european trees: The arboreal system of a prehistoric people. University of Chicago Press.
Cita Chicago (17th ed.)
Friedrich, Paul. Proto-indo-european Trees: The Arboreal System of a Prehistoric People. Chicago: University of Chicago Press, 1970.
Cita MLA (9th ed.)
Friedrich, Paul. Proto-indo-european Trees: The Arboreal System of a Prehistoric People. University of Chicago Press, 1970.
Atenció: Aquestes cites poden no estar 100% correctes.