Todd, Lewis Paul
Harcourt Brace Jovannovich, 1972
Buku Teks SO
Patrick, John
Macmillan, 1984
Buku Teks SO
Alden, John Richard
Harper & Row Publishers, 1963
Buku Teks SO
Diggins, John Patrick
W.W Norton, 1992
Buku Teks SO
Vaillant, George C.
Penguin Books, 1950
Buku Teks