Rourke Publishing LLC, 2009
Buku Referensi
McEvery, Colin
Facts On File, 1979
Buku Referensi
edited by Geoffrey Barraclough
Times Books, 1984
Buku Referensi
McNally, Rand
Rand McNally & Co, 1957
Buku Referensi
London Chancellor Press 1999,
Buku Referensi