Key, Mary Ritchie, author
Tubingen Gunter Narr Verlag 1979
Buku Teks
Feder, Norman
H. N. Abrams, 1973
Buku Teks
Handlin, Oscar, author
An Atlantic Monthly Press Book, 1973
Buku Teks
Kim, Ye-kyoum, author
[Publisher not identified], 2004
Artikel Jurnal
Unrau, Harlan D.
National Park Service, 1976
Buku Teks