Use Library Search to find books, government documents, and other library materials owned by or made available through TU Libraries. Search by both corporate author, i.e. for the "United States National Park Service" as the corporate author of government documents relating to your park or unit, and by keyword or subject for your particular park. For example, "Yellowstone National Park."
For newspaper coverage of your NPS park or unit from the past couple decades (assignment #3) try.:
The United States Government Manual is published annually. It contains information about executive branch agencies including the Department of the Interior and the National Park Service. A researcher might use The U.S. Government Manual to find the names of NPS directors and other officials for a certain presidential administration. The manuals show how the structure and purpose of Interior Department agencies changed over time. Descriptions of agencies sometimes include references to legislative acts and executive orders that can be searched in one of the government documents databases listed on the homepage of this guide.