APA

American Petroleum Institute A., . (2013). Recommended practice for installation, maintenance, and lubrication of pumping units. Washington: American Petroleum Institute, API.

Chicago

American Petroleum Institute API, . 2013. Recommended practice for installation, maintenance, and lubrication of pumping units. Washington: American Petroleum Institute, API.

Harvard

American Petroleum Institute A., . (2013). Recommended practice for installation, maintenance, and lubrication of pumping units. Washington: American Petroleum Institute, API.

MLA

American Petroleum Institute API, . Recommended practice for installation, maintenance, and lubrication of pumping units. Washington: American Petroleum Institute, API. 2013.