McEvery, Colin, author
Facts On File, 1979
Buku Referensi
Golden Press, 1966
Buku Referensi
edited by Geoffrey Barraclough
Times Books, 1984
Buku Referensi
McNally, Rand, author
Rand McNally & Co, 1957
Buku Referensi
edited by Year
Oxford Paper, 1956
Buku Teks