Dyfyniad APA

Babbie, E. R. (1990). Survey research methods (2nd ed.). California.

Dyfyniad Arddull Chicago

Babbie, Earl R. Survey Research Methods. 2nd ed. Belmont: California, 1990.

Dyfyniad MLA

Babbie, Earl R. Survey Research Methods. 2nd ed. California, 1990.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.