Causal inferences in nonexperimental research, 2026-02-16T04:12:06+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - Blalock, Hubert M. (University of North Carolina Press, 1964)