Government publications are written by federal bureaucrats and printed, not published, by the Government Printing Office.
Many government publications are now "published" on the web, either simultaneously with a print version, or exclusively online.
The author will be an individual or an agency.
The publisher will be an agency or bureau or division.
Very often these publications will not follow a standard title page arrangement and some publishing elements will be eliminated. Include whatever information is available for citing in any style, and simply leave out the information that is not provided.