Columbia subject headings:
Conservation of natural resources--United States.
Hetch Hetchy Valley (Calif.)
Muir, John, 1838-1914.
Sierra Club.
Yosemite National Park (Calif.)
Harvard subject headings:
Hetch Hetchy Valley (Calif.)
Muir, John, 1838-1914
Sierra Club
Yosemite National Park (Calif.)
Princeton subject headings:
Hetch Hetchy Valley (Calif.)
Muir, John, 1838-1914.
Sierra Club.
Yosemite National Park (Calif.)