1. Code of Federal Regulations (1991). Office of the Federal Register, National Archives and Records Administration, Title 40, Part 258, US Government Printing Office, 9 October.
2. Alternative daily cover materials for landfills;US EPA,1991
3. Alternative daily cover material for landfill use;Environmental Network,1991
4. Landfill reclamation: An alternative to closure and siting;Morelli,1991
5. Solid waste disposal facility criteria; final rule. 40 CFR 257 and 258;Federal Register,1991