Gebhard, L., & Gomringer, E. (1980). Distanzsignale: Ludwig Gebhard, Eugen Gomringer.
Cita Chicago (17th ed.)Gebhard, Ludwig, i Eugen Gomringer. Distanzsignale: Ludwig Gebhard, Eugen Gomringer. 1980.
Cita MLA (8th ed.)Gebhard, Ludwig, i Eugen Gomringer. Distanzsignale: Ludwig Gebhard, Eugen Gomringer. 1980.
Atenció: Aquestes cites poden no estar 100% correctes.