Cita APA (7a ed.)

Heer, F. (1975). Charlemagne and his world. MacMillan.

Cita Chicago Style (17a ed.)

Heer, Friedrich. Charlemagne and His World. New York: MacMillan, 1975.

Cita MLA (9a ed.)

Heer, Friedrich. Charlemagne and His World. MacMillan, 1975.