"Great Lakes – U.S. EPA". Epa.gov. 2006-06-28. Archived from the original on 2012-12-01. Retrieved 2011-02-19. Note: by 'surface' is meant 'as measured by surface area'. Measured by volume it would no doubt be a lesser figure.
"Great Lakes – U.S. EPA". Epa.gov. 2006-06-28. Archived from the original on 2012-12-01. Retrieved 2011-02-19. Note: by 'surface' is meant 'as measured by surface area'. Measured by volume it would no doubt be a lesser figure.