Geological Survey (U.S.) & Anderson, R. M. (2000). Water quality in the Allegheny and Monongahela River Basins: Pennsylvania, West Virginia, New York, and Maryland, 1996-98. U.S. Geological Survey, National NAWQA Program Free on application to the U.S. Geological Survey, Information Services.
Cita Chicago (17th ed.)Geological Survey (U.S.) i Robert M. Anderson. Water Quality in the Allegheny and Monongahela River Basins: Pennsylvania, West Virginia, New York, and Maryland, 1996-98. Reston, VA, Denver, CO: U.S. Geological Survey, National NAWQA Program Free on application to the U.S. Geological Survey, Information Services, 2000.
Cita MLA (9th ed.)Geological Survey (U.S.) i Robert M. Anderson. Water Quality in the Allegheny and Monongahela River Basins: Pennsylvania, West Virginia, New York, and Maryland, 1996-98. U.S. Geological Survey, National NAWQA Program Free on application to the U.S. Geological Survey, Information Services, 2000.