Alden, John Richard, author
Harper & Row Publishers, 1963
Buku Teks
Green, Constance McLaughlin, 1897-1975
Harper & Row, Publishers, 1965
Buku Teks
Harvie, Christopher T
0, 1994
Buku Teks
Thomson, Ian, author
John Murray, 1957, 1960
Buku Teks
Hsu, Immanuel C.Y.
Oxford University Press, 1970
Buku Teks