Batschelet, Edward
Springer-Verlag , 1975
Buku Teks
Richman, Fred, author
Brooks/Cole, 1967
Buku Teks
Chartrand, Gary, author
Pearson Addison Wesley, 2008
Buku Teks
Rosen, Kenneth H., author
McGraw-Hill, 1999
Buku Teks
Devlin, Keith
Chapman & Hall, 1992
Buku Teks