Cita APA (7a ed.)

(1989). Dietz-Geschichtskalender 1990 (o.A.). Dietz.

Cita Chicago Style (17a ed.)

Dietz-Geschichtskalender 1990. o.A. Berlin: Dietz, 1989.

Cita MLA (8a ed.)

Dietz-Geschichtskalender 1990. o.A. Dietz, 1989.