Dobson, Ann
grolier international, 1999
Buku Teks
Raines, Claire, author
American Management Association, 2006
eBooks
Iacone, Salvatore J., author
Carrer Press, 2003
Buku Teks
Simmons, Annette, author
American Management Association, 2007
eBooks
Dobson, Ann, author
Glorier International Inc., 1999
Buku Referensi