Tichelmann, Karsten
Birkhauser GmbH, 2008
Buku Referensi
Duran, Sergi Costa
Page One , 2011
Buku Referensi
Thiede, Sebastian, editor
[Springer, ], 2012
eBooks
Anderson, Victor
Routledge, 1993
Buku Teks
Flavin, Christopher
Worldwatch Institute, 1988
Buku Teks