Knook, Allard, author
Utrecht University, 2009
Buku Teks
Brown, L. Neville (Lionel Neville), author
Sweet and Maxwell, 1994
Buku Teks
Broberg, Morten P.
United Kingdom Oxford university Press, 2014
Buku Teks
Nugent, Neill, author
Macmillan, 1994
Buku Teks
edited by Mark Dawson, Bruno De Witte and Elise Muir
Edward Elgar Publishing, 2013
Buku Teks