Psacharopoulos, George, author
World Bank, c1980
Buku Teks
Mishan, E. J., author
Routledge, 1972
eBooks
Beeby, C. E., author
Harvard University Press, 1966
Buku Teks
Ray, Anandarup
The Johns Hopkins University Press, 1984
Buku Teks
editor, Cat Sharpe
[American Society for Training and Development Press, American Society for Training and Development Press], 1997
eBooks