Lewis-Beck, M. S. (1990). Experimental design and methods. Sage.
Dyfyniad Arddull ChicagoLewis-Beck, Michael S. Experimental Design and Methods. London: Sage, 1990.
Dyfyniad MLALewis-Beck, Michael S. Experimental Design and Methods. Sage, 1990.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.