Stockmann, Petra, author
Hanns Seidel Foundation; Watch Indonesia, 2007
Buku Teks
Artikel Jurnal
Salas, Rafael M., author
Pergamon Press, 1979
Buku Teks
Congalton, Russel G., author
CRC Press, Taylor & Francis Group, 2009
Buku Teks
Gregory, Robert Henry, author
Wadsworth, 1960
Buku Teks