Boschere, Jean De
Editions Du Cerele D`art, 1947
Buku Teks
Kanter, Jerome
Englewood Cliffs, N.J. Prentice-Hall 1992,
Buku Referensi
Jerome, Harry
Routledge , 1934
Buku Teks
Kanter, Jerome
Prentice-Hall, 1992
Buku Teks SO
O`Brien, Larry
Ruotledge , 1992
Buku Teks SO