National Park Service
A Visitor Study by the National Park Service, Yellowstone National Park, and facilitated by Otak, RRC Associates, and the University of Montana Institute for Tourism and Recreation Research.
Jorgenson, Jake; Sage, Jeremy; Nickerson, Norma; Bermingham, Carter; Otak Inc.; and White, Christina, "Yellowstone National Park Visitor Study Executive Summary" (2019). Institute for Tourism and Recreation Research Publications. 396.