Lewis, D. G. (1968). Experimental design in education. University of London P..
Lua i Stíl Chicago (17ú heag.)Lewis, D. G. Experimental Design in Education. London: University of London P., 1968.
Lua MLA (8ú heag.)Lewis, D. G. Experimental Design in Education. University of London P., 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.