Esworthy, Robert. 2006 National Ambient Air Quality Standards (NAAQS) for Fine Particulate Matter (PM2.5): Designating Nonattainment Areas. Washington D.C.. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc122190/. Accessed July 27, 2016.
Note: Inconsistencies in capitalization and punctuation within the Digital Library may affect this citation. Before using this citation in formal writing, please consult your preferred style manual. More information.