共 26 条
[21]
YELIN EH, 1980, MILBANK MEM FUND Q, P58
[22]
1966, DICT OCCUPATIONAL S
[23]
1965, DICT OCCUPATIONAL TI, V2
[24]
1977, SSA7711978 HEW PUB
[25]
1974, HRA771537 DHEW PUB
[26]
1977, STATISTICAL ABSTRACT, P75