APA (7th ed.) Citation

(1995). Mud volcano (Revised April 1995.). Yellowstone Association in cooperation with the National Park Service.

Chicago Style (17th ed.) Citation

Mud Volcano. Revised April 1995. Yellowstone National Park, Wyoming: Yellowstone Association in cooperation with the National Park Service, 1995.

MLA (9th ed.) Citation

Mud Volcano. Revised April 1995. Yellowstone Association in cooperation with the National Park Service, 1995.