Cita APA (7th ed.)

Leffler, W. L., & Womack, K. (2014). Natural gas liquids: A nontechnical guide. PennWell Corporation.

Cita Chicago (17th ed.)

Leffler, William L., i Karla Womack. Natural Gas Liquids: A Nontechnical Guide. Tulsa, Oklahoma: PennWell Corporation, 2014.

Cita MLA (9th ed.)

Leffler, William L., i Karla Womack. Natural Gas Liquids: A Nontechnical Guide. PennWell Corporation, 2014.