APA (7th ed.) Citation

Popp, D. (1990). Offene Grenze, offene Verkehrsfragen.

Chicago Style (17th ed.) Citation

Popp, Dieter. Offene Grenze, Offene Verkehrsfragen. 1990.

MLA (9th ed.) Citation

Popp, Dieter. Offene Grenze, Offene Verkehrsfragen. 1990.

Warning: These citations may not always be 100% accurate.