Patrick, John
Macmillan Publishing Company, 1984
Buku Teks
Quint, Howard H
Dorsey Press, 1968
Buku Teks
Adams, James Truslow
1946
Buku Referensi
editor Thomas C. Cochran, Wayne Andrew
Charles Scribner's Sons , 1962
Buku Referensi
Dull, Jonathan R
Yale University Press, 1985
Buku Teks