APA (7th ed.) Citation

Nature Conservancy (U.S.), Geological Survey (U.S.), & Bailey, R. G. (1998). Ecoregions map of North America: Explanatory note. U.S. Dept. of Agriculture, Forest Service.

Chicago Style (17th ed.) Citation

Nature Conservancy (U.S.), Geological Survey (U.S.), and Robert G. Bailey. Ecoregions Map of North America: Explanatory Note. [Washington, D.C.]: U.S. Dept. of Agriculture, Forest Service, 1998.

MLA (9th ed.) Citation

Nature Conservancy (U.S.), et al. Ecoregions Map of North America: Explanatory Note. U.S. Dept. of Agriculture, Forest Service, 1998.