"The Potomac River Valley : an object lesson for development by interstate co-operation."; "Birchfield, James."; "Interstate Commission on the Potomac River Basin."; "Potomac River Valley--Economic conditions.", "Potomac River Valley--Social conditions."; "Pollution--Health aspects.", "Pollution--Environmental aspects--United States.", "Pollution control industry.", "Pollution--Government policy."; "Birchfield, James."; "undated"; "Pamphlet. Reprint of a series of newspaper articles from: The Evening Star (Washington, D.C.). Includes the results of a survey of the Potomac River Basin."; ""; "P228"; "pec"; "Potomac River Valley--Economic conditions.", "Pollution control industry.", "Pollution--Health aspects.", "Pollution--Environmental aspects--United States.", "Pollution--Government policy.", "Potomac River Valley--Social conditions.", "Interstate Commission on the Potomac River Basin."; "14256"; .