Orphan Drug Reauthorization: Hearing Before the Subcommittee on Health and the Environment of the Committee on Energy and Commerce, House of Representatives, One Hundred Third Congress, Second Session on H.R. 4160, a Bill to Amend the Federal Food, Drug, and Cosmetic Act, the Public Health Service Act, and the Orphan Drug Act to Revise the Provisions of Such Acts Relating to Orphan Drugs, June 16, 1994, Volume 4