Experimental and quasi-experimental designs for research 2026-02-16T05:22:16+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - Campbell, Donald T. (Donald Thomas), 1916-1996.x; Stanley, Julian C (Houghton Mifflin, 1963)