title: Proficiency Analytical Testing (PAT) Program November 1999.
authors.affiliation: HHS/PHS/CDC/NIOSH, Cincinnati, OH 45226, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Feng
authors.forename: P
authors.initials: P
authors.lastname: Schlecht
mesh_terms: D004785:Environmental Pollutants / Q000032:analysis* / Q000592:standards*; D007753:Laboratories / Q000592:standards*; D009314:National Institute for Occupational Safety and Health, U.S.; D012015:Reference Standards; D014481:United States
chemical_list: D004785:Environmental Pollutants