Carnegie, Dorothy
Dale Carnegie and Associates, 1962
Buku Teks
Seagraves, Theresa
American Society for Training and Development Press, 2004
eBooks
Guth, Hans P.
Wadsworth, 1969
Buku Teks
selected and introduced by Carl Harrison-Ford; foreword by Osmar White
Lothian , 1986
Buku Teks
Margaret Anzul
Routledge, 2001
Buku Teks