Artikel Jurnal
Clason, W. E., 1898-, author
Elsevier Scientific Publishing, 1976
Buku Referensi
Artikel Jurnal
Thiagarajan, Sivasailam, author
American Society for Training & Development, 2007
eBooks
Yabuka, Narelle, author
an\b editions, 2010
Buku Referensi