APA (7e ed.) Bronvermelding

Geological Survey (U.S.). (1953). Interpreting geologic maps for engineering purposes: Hollidaysburg quadrangle, Pennsylvania.

Chicago (17e ed.) Bronvermelding

Geological Survey (U.S.). Interpreting Geologic Maps for Engineering Purposes: Hollidaysburg Quadrangle, Pennsylvania. Washington, 1953.

MLA (8e ed.) Bronvermelding

Geological Survey (U.S.). Interpreting Geologic Maps for Engineering Purposes: Hollidaysburg Quadrangle, Pennsylvania. 1953.

Let op: Deze citaties zijn niet altijd 100% accuraat.