Mcewen, Sir Robert
Sweet & Maxwell, 1979
Buku Teks
Lawhorne, Clifton O., author
Southern Illinois University Press, 1971
Buku Teks
Artikel Jurnal
Wieringa, Saskia Eleonora, 1950-, author
YJP Press, 2015
Artikel Jurnal
Rose, Arnold M., author
University of minnesota Press, 1968
Buku Teks