If you are looking for United States government sources, visit Database Finder and navigate to "Browse Database by Subject" and select "Government Documents (U.S)."
If you are looking for information on governments outside the U.S., visit Database Finder and navigate to "Browse Database by Subject" and select "Government and Politics"
If your presentation topic has anything to do with politics or public policy, government sources are an excellent source of information on current policy and related statistics.
