Cita APA (7th ed.)

Honnef, K., & Leonhard, M. (1990). Leonhard: Portraits. Cantz.

Cita Chicago (17th ed.)

Honnef, Klaus, i Mark Leonhard. Leonhard: Portraits. Stuttgart: Cantz, 1990.

Cita MLA (8th ed.)

Honnef, Klaus, i Mark Leonhard. Leonhard: Portraits. Cantz, 1990.