APA

American Gas Association A., . (2009). Natural gas contract measurement and quality clauses. Washington: American Gas Association, AGA.

Chicago

American Gas Association AGA, . 2009. Natural gas contract measurement and quality clauses. Washington: American Gas Association, AGA.

Harvard

American Gas Association A., . (2009). Natural gas contract measurement and quality clauses. Washington: American Gas Association, AGA.

MLA

American Gas Association AGA, . Natural gas contract measurement and quality clauses. Washington: American Gas Association, AGA. 2009.