National Science Foundation (U.S.). (1969). Scientific technical and health personnel in the federal government 1969. U.S. Government Printing Office.
芝加哥风格引文National Science Foundation (U.S.). Scientific Technical and Health Personnel in the Federal Government 1969. Washington, D.C: U.S. Government Printing Office, 1969.
MLA引文National Science Foundation (U.S.). Scientific Technical and Health Personnel in the Federal Government 1969. U.S. Government Printing Office, 1969.
警告：这些引文格式不一定是100％准确.