Freight Rates for Recyclable Materials: Hearings Before the Subcommittee on Transportation and Aeronautics of the Committee on Interstate and Foreign Commerce, House of Representatives, Ninety-third Congress, Second Session, on H.R. 6637 (and All Identical Bills) Bills to Encourage the Movement in Interstate and Foreign Commerce of Recycled and Recyclable Materials and to Reduce the Quantities of Solid Waste Materials in Commerce which Cannot be Recycled Or Do Not Contain Available Recycled Materials, and for Other Purposes ; H.R. 12536 (and All Identical Bills) Bills to Protect the Environment and Conserve Natural Resources by Stimulating the Use of Recycled and Recyclable Materials by Effecting Rate Changes in the Movement of These Materials by Common Carrier, and for Other Purposes, March 12, 13, and 14, 1974