APA

American Petroleum Institute A., . (2021). Butterfly valves: double flanged, lug and wafer type, and butt-welding ends. Washington: American Petroleum Institute, API.

Chicago

American Petroleum Institute API, . 2021. Butterfly valves: double flanged, lug and wafer type, and butt-welding ends. Washington: American Petroleum Institute, API.

Harvard

American Petroleum Institute A., . (2021). Butterfly valves: double flanged, lug and wafer type, and butt-welding ends. Washington: American Petroleum Institute, API.

MLA

American Petroleum Institute API, . Butterfly valves: double flanged, lug and wafer type, and butt-welding ends. Washington: American Petroleum Institute, API. 2021.