edited by Geoffrey Barraclough
Times Books, 1984
Buku Referensi
McNally, Rand, author
Rand McNally & Co, 1957
Buku Referensi
C.S. Hammond , 1961
Buku Referensi
The George F. Cram, 1952
Buku Referensi
de Lange, Nicholas, author
Andromeda, 1992
Buku Referensi