Spickett, Gavin
Oxford University Press, 1999
Buku Referensi
Murray Longmore [and others]
Oxford University press, 2014
Buku Teks
Wiley Blackwell, 2015
Buku Teks SO
edited by Daniel Bodansky, Jutta Brunnee and Ellen Hey
University of Oxford Press, 2008
Buku Teks SO
Goran Koch; Sven Poulsen
Wiley Blackwell, 2009
Buku Teks SO