Harpers Ferry ; Niobrara River ; and Council Bluffs, Iowa Trails Interpretation Center : hearing before the Subcommittee on Public Lands, National Parks, and Forests of the Committee on Energy and Natural Resources, United States Senate, One Hundred First Congress, first session, on S. 85 ... S. 280 ... S. 338 ... April 5, 1989. (U.S. G.P.O. :, 1989)