TY  - BOOK
AU  - Blalock,Hubert M
TI  - Causal inferences in nonexperimental research
T2  - The Norton library,
SN  - 0393006425
AV  - H61 .B48 1972
U1  - 300.72 22
PY  - 1964///
CY  - New York
PB  - University of North Carolina Press
KW  - Social sciences
KW  - Mathematical models
N1  - Bibliography: p. 193
ER  -