APA (7e ed.) Bronvermelding

Blalock, H. M. (1964). Causal inferences in nonexperimental research. University of North Carolina.

Chicago (17e ed.) Bronvermelding

Blalock, Hubert M. Causal Inferences in Nonexperimental Research. Chapel Hill: University of North Carolina, 1964.

MLA (9e ed.) Bronvermelding

Blalock, Hubert M. Causal Inferences in Nonexperimental Research. University of North Carolina, 1964.