Can you tell us what fields each of the items is stored in?
when editing the output style>click on reference types and click on Government Document, to have that listed. Then I usually start by copying the “generic” and work from there. So far I would have rearranged and edited to something like this:
Author (separate field). |Year|. Title.| City|: Publisher| Congress Number.
if
Author (or should it be Department???): U.S. Government Accountability Office (GAO)
???: (GAO) (Is this a part of the above, or a separate field?) (I recommend a separate field)
Year: 2006.
Title: Title Title Title.
Place Published: Washington, DC:
Publisher: Government Printing Office.
Congress Number???: GAO-06-844T