C93 (field experiment), J24 (Human Capital • Skills • Occupational Choice • Labor Productivity
A23, C93, J24, O31, L86, I31
26, J24, D83, D84
I26, J38, J24, J23
Health, Education and Welfare
I21, I25, J13, J24, O15, C93
I12, I15, I25, J15, O15
J24, J3
K42, I26, J13, J24
C93, D83, D91, J24, M51, O15