Manchester Open Learning; alih bahasa, Marcus Prihminto Widodo
Gramedia Pustaka Utama, 1997
Buku Teks
Dunckel, Jacqueline
Self-Counsel, 1984
Koleksi Publik
McGraw-Hill, 2003
Buku Teks
Brusino, Justin
American Society for Training & Development, 2008
eBooks
Atwood, Christee Gabour
American Society for Training & Development, 2007
eBooks