APA (7th ed.) Citation

Heyl, A. V. (1951). Exploratory drilling in the Prairie du Chien group of the Wisconsin zinc-lead district by the U.S. Geological Survey in 1949-1950. [publisher not identified].

Chicago Style (17th ed.) Citation

Heyl, Allen V. Exploratory Drilling in the Prairie Du Chien Group of the Wisconsin Zinc-lead District By the U.S. Geological Survey in 1949-1950. [Washington]: [publisher not identified], 1951.

MLA (8th ed.) Citation

Heyl, Allen V. Exploratory Drilling in the Prairie Du Chien Group of the Wisconsin Zinc-lead District By the U.S. Geological Survey in 1949-1950. [publisher not identified], 1951.