Fowler, F. J. (1997). Survey research methods. Beverly Hills: Sage Publications.
Dyfyniad Arddull ChicagoFowler, Floyd J. Survey Research Methods. Beverly Hills: Sage Publications, 1997.
Dyfyniad MLAFowler, Floyd J. Survey Research Methods. Beverly Hills: Sage Publications, 1997.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.