Rabe, Cynthia Barton, author
American Management Association, 2006
eBooks
Sullivan, Walter, author
McGraw-Hill, 1966
Buku Teks
Eskens, Allen, author
Noura Books, 2017
Buku Teks
O`Dell, Carla
Free Press , 1998
Buku Teks
Lee, Su-yeol, author
Hyeonamsa, 2006
Buku Teks