APA (7th ed.) Citation

Wood, G. H., & Bour, W. V. (1988). Coal map of North America. U.S. Geological Survey.

Chicago Style (17th ed.) Citation

Wood, Gordon H., and William V. Bour. Coal Map of North America. Reston, Va.: U.S. Geological Survey, 1988.

MLA (9th ed.) Citation

Wood, Gordon H., and William V. Bour. Coal Map of North America. U.S. Geological Survey, 1988.