Cita APA (7a ed.)

Duerr, J., Klett, T., & Treuber, O. (1896). Mittelalter. Neff.

Cita Chicago Style (17a ed.)

Duerr, Julius, Theodor Klett, y Oskar Treuber. Mittelalter. Stuttgart: Neff, 1896.

Cita MLA (9a ed.)

Duerr, Julius, et al. Mittelalter. Neff, 1896.