Gaya APA
Blalock, H, M. (1964).
Causal Inferences in Nonexperimental Research .
Chapel Hill:
The University of North Carolina Press.
Gaya MLA
Blalock, Hubert, M.
"Causal Inferences in Nonexperimental Research".
Chapel Hill:
The University of North Carolina Press,
1964.
Text.