Nielsen, Kaj L.
Cliff's Notes, [Date of publication not identified]
Buku Teks
Palmer, Claude Irwin
McGraw-Hill, 1994
Buku Teks SO
Johson, David B.
Grove Brooks/Cole, 1999
Buku Teks
Juszli, Frank L.
Prentice-Hall, 1969
Buku Teks
Schaaf, William L.
Wiley-Academy, 1965
Buku Teks SO