Csapo, Tamas, editor
Springer, 2012
eBooks
Kweku-Muata Osei-Bryson, Gunjan Mansingh, Lila Rao
Springer, 2014
Buku Teks
HMSO , 1995
Buku Teks
Bruch, Mathias, author
Westview Press, 1984
Buku Teks
editor, Walter B. Stohr, D.R. Fraser Taylor
John Wiley & Sons, 1981
Buku Teks