Start with a keyword search in the catalog. Once you have located a relevant item, you can look at the Library of Congress Subject Headings within the full record tab and follow those links to find related books.
UNC holds over two million Federal, international, and state documents, but not all of these are in the catalog. Still, the catalog is a great place to start your research, particularly for documents published after 1976. Use the Advanced Search page to limit the location to Davis Library Government Documents.
Here are some sample subject headings from the library catalog. You can also add your country as a keyword to refine your search.
For keyword searches, try:
Use the "search within results" checkbox to add keywords and increase specificity.