London Routledge , 1992
Buku Teks SO
Soenarjati Djajanegara
2005
Artikel Jurnal
edited by Martin Coyele, Peter Garside, Malcolm Kelsall, John Peck
Routledge, 1991
Buku Referensi
edited by Martin Coyle ... [and others]
Gale Research, 1991
Buku Referensi
Watt, Homer A.
Scott, Foresman, 1932
Buku Teks