APA (7th ed.) Citation

Ravndal, G. B. (1930). German concrete mixer production. [publisher not identified].

Chicago Style (17th ed.) Citation

Ravndal, G. Bie. German Concrete Mixer Production. Washington, D.C.: [publisher not identified], 1930.

MLA (9th ed.) Citation

Ravndal, G. Bie. German Concrete Mixer Production. [publisher not identified], 1930.