==External links==* NPS official website* National Park Service in the Federal Register* NPS Research Links/Reference Desk* NPS Library Information Center* NPS Focus Digital Library & Research Station* NPS Historic Photograph Collection* NPS B-Roll Video (public domain)* NPS Digital Image Archives (public domain)* NPS Civil War Soldiers and Sailors System (CWSS)* Community Assistance Available from the National Park Service* Criteria for inclusion in the National Park System* Designation of National Park System Units (national monument vs national park, etc.)
==Liên kết ngoài==* NPS official website* NPS Research Links/Reference Desk* NPS Library Information Center* NPS Focus Digital Library & Research Station* NPS Historic Photograph Collection* NPS B-Roll Video (public domain)* NPS Digital Image Archives (public domain)* NPS Civil War Soldiers and Sailors System (CWSS)* Community Assistance Available from the National Park Service* Criteria for inclusion in the National Park System* Designation of National Park System Units (national monument vs national park, etc.)