Korean National Tourism Corporation, [date of publication not identified]
Buku Referensi
Gray, Basil
Faber and Faber Ltd, 1959
Buku Teks
Priest, Alan
[T.p.] , 1944
Buku Teks
Lawick-Goodall, Jane van
Houghton Mifflin, 1971
Buku Teks
Price, Willard
Willam Heinemann , 1944
Buku Teks