Nye, Joseph S., author
Longman, 1997
Buku Teks
Knutsen, Torbjorn L.
Manchester University Press, 1992
Buku Teks
Tannsjo, Torbjorn, author
Edinburgh University Press, 2010
Buku Teks
Nye, Joseph S., author
Essex Pearson, 2014
Buku Teks
Nye, Joseph S., author
Pearson, 2012
Buku Teks