Christensen, C. Roland
Harvard University, 1953
Buku Teks
Stepanek, Joseph E.
The Free Press , 1960
Buku Teks
Perry, Martin
RajaGrafindo Persada, 2000
Buku Teks
by Curtis E. Tate Jr. ... [and others]
Business Publication, 1982
Buku Teks
Hodgetts, Richard M.
Harcourt College Publishers, 2001
Buku Teks