Gibbon, Edwards
New York : The Modern Library, [t.th].
Buku Teks
Rives, James B., author
Blackwell, 2007
Buku Teks
Boren, Henry C., author
D.C. Heath and Company, 1977
Buku Referensi
Read, H.H., author
ELBS and Macmillan, 1975
Buku Teks
ESCAP , 1975
Buku Teks