Barnow, Erik
Oxford Univ. Press, 1970
Buku Teks
Head, Sydney W.
Houghton Miffiln, 1987
Buku Teks
Comstock, George
Sage, 1991
Buku Teks
editor Thomas C. Cochran, Wayne Andrew
Charles Scribner's Sons , 1962
Buku Referensi
Brinkley, Alan
McGraw-Hill, 1997
Buku Referensi