(1989). Air contaminants: Permissible exposure limits (Title 29 Code of federal regulations, part 1910.1000).
芝加哥风格引文Air Contaminants: Permissible Exposure Limits (Title 29 Code of Federal Regulations, Part 1910.1000). 1989.
MLA引文Air Contaminants: Permissible Exposure Limits (Title 29 Code of Federal Regulations, Part 1910.1000). 1989.
警告：这些引文格式不一定是100％准确.