共 8 条
[1]
DAVIS RA, 1935, ED ADM SUPERVISION, V21, P137
[4]
LEVINE S, 1957, NONGROUP ENROLLMENT
[6]
PARTEN M, 1950, SURVEYS POLLS SAMPLE, P366
[7]
Waisanen FB., 1954, PUBLIC OPIN Q, V18, P210
[8]
Wallace D, 1954, PUBLIC OPIN QUART, V18, P40, DOI 10.1086/266484