APA

American Petroleum Institute A., . (2002). Engine oil licensing and certification system. Washington: American Petroleum Institute, API.

Chicago

American Petroleum Institute API, . 2002. Engine oil licensing and certification system. Washington: American Petroleum Institute, API.

Harvard

American Petroleum Institute A., . (2002). Engine oil licensing and certification system. Washington: American Petroleum Institute, API.

MLA

American Petroleum Institute API, . Engine oil licensing and certification system. Washington: American Petroleum Institute, API. 2002.