This print ISBN is the U.S. Federal Government official edition. 40CFR, Pt. 63 (63.1440-63.6175), continues coverage of Protection of Environment, Environmental Protection Agency (EPA)--Air Programs. This publication includes National Emission Standards for Hazardous Air Pollutants for Source Categories.Related items: The Annual CFR Print Subscription can be found here: https: //bookstore.gpo.gov/products/code-federal-regulations-subscription-service-2017-paperback-0CFR Title 40, Protection of Environment publications can be found here: https: //bookstore.gpo.gov/catalog/cfr-title-40-protection-environmentEnvironment & Nature resources collection is available here: https: //bookstore.gpo.gov/catalog/environment-nature