APA (7th ed.) Citation

Mills, A., & Pritchard, J. (1991). A "40 Feet" Oil Barometer.

Chicago Style (17th ed.) Citation

Mills, Allan, and John Pritchard. A "40 Feet" Oil Barometer. 1991.

MLA (9th ed.) Citation

Mills, Allan, and John Pritchard. A "40 Feet" Oil Barometer. 1991.

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