Cohen, Isabelle; Freiling, Thomas; Robinson, Eric (January 2012). The Economic Impact and Financing of Infrastructure Spending(PDF) (report). Williamsburg, Virginia: Thomas Jefferson Program in Public Policy, College of William & Mary. p. 5. Archived from the original(PDF) on May 3, 2012. Retrieved October 1, 2012.
Cohen, Isabelle; Freiling, Thomas; Robinson, Eric (January 2012). The Economic Impact and Financing of Infrastructure Spending(PDF) (report). Williamsburg, Virginia: Thomas Jefferson Program in Public Policy, College of William & Mary. p. 5. Archived from the original(PDF) on May 3, 2012. Retrieved October 1, 2012.