APA
American Petroleum Institute A., . (2007). Recommended practice for installation, maintenance, and repair of surface safety valves and underwater safety valves offshore. Washington: American Petroleum Institute, API.
Chicago
American Petroleum Institute API, . 2007. Recommended practice for installation, maintenance, and repair of surface safety valves and underwater safety valves offshore. Washington: American Petroleum Institute, API.
Harvard
American Petroleum Institute A., . (2007). Recommended practice for installation, maintenance, and repair of surface safety valves and underwater safety valves offshore. Washington: American Petroleum Institute, API.
MLA
American Petroleum Institute API, . Recommended practice for installation, maintenance, and repair of surface safety valves and underwater safety valves offshore. Washington: American Petroleum Institute, API. 2007.