Mann, Leon
Sydney John Wiley & Sons 1969,
Buku Teks
Blackwell Publishing Limited - The Japan Group dynamics Association, 2007,
Majalah, Jurnal, Buletin
Garton, Alison F
Hove Lawrence Erlbaum Associates , 1995
Buku Teks SO
Fromm, Erich
London and New York : Routledge, 2002
Buku Teks
Beverly Hills Sage 1988,
Buku Teks