edited by Edmund S. Morgan
Prentice-Hall, 1965
Buku Teks SO
edited by Edmund S. Morgan
Prentice-Hall, 1965
Buku Teks SO
Morris, Richard B.
Van Nostrand Reinhold, 1955
Buku Teks SO
Unrau, Harlan D.
National Park Service, 1976
Buku Teks SO
Miller, John C.
Stanford University Press, 1965
Buku Teks