title: Court shuts down retroactive rules.
authors.forename: D
authors.initials: D
authors.lastname: Burda
mesh_terms: D004219:District of Columbia; D007882:Legislation, Hospital; D006278:Medicare / Q000331:legislation & jurisprudence*; D013997:Time Factors; D014481:United States; D014483:United States Dept. of Health and Human Services