edited by Geoffrey Barraclough
Times Books, 1984
Buku Referensi
The George F. Cram, 1952
Buku Referensi
C.S. Hammond & Company
C.S. Hammond & Company, 1958
Buku Teks
McNally, Rand
Rand McNally & Co, 1957
Buku Referensi
Robinson, Francis
Facts on File, 1982
Buku Referensi