Nickerson, Raymond S., author
Lawrence Erlbaum Associates , 2003
Buku Teks
Bonnes, Mirilia, author
Sage, 1995
Buku Teks
Harcourt Brace College, 1996
Buku Teks
Heimstra, Norman W.
Brooks/Cole, 1978
Buku Teks
Istiqomah Wibowo, author
Fakultas Psikologi Universitas Indonesia, 2009
Artikel Jurnal