Columbia subject headings:
Colorado--Description and travel.
Mexico--Description and travel.
Rocky Mountains.
West (U.S.)--Description and travel.
Harvard subject headings:
Mexico--Description and travel.
Rocky Mountains--Description and travel.
West (U.S.)--Description and travel.
Princeton subject headings:
Colorado--Description and travel.
Mexico--Description and travel.
Rocky Mountains
West (U.S.)--Description and travel.