1. Davidson, E. A.; David, M. B.; Galloway, J. N.; Goodale, C. L.; Haeuber, R.; Harrison, J. A.; Howarth, R. W.; et al.Excess Nitrogen in the U.S. Environment: Trends, Risks, and Solutions.Issues in Ecology, 2012; Report No.15
2. U.S. EPA. Reactive Nitrogen in the United States: An Analysis of Inputs, Flows, Consequences, and Management Options, EPA-SAB-11-013; EPA Science Advisory Board, 2011; p140.
3. Eutrophication and harmful algal blooms: A scientific consensus
4. Spreading Dead Zones and Consequences for Marine Ecosystems