Dooley, D. (1984). Social research methods. Prentice-Hall.
Dyfyniad Arddull ChicagoDooley, David. Social Research Methods. Englewood Cliffs, N.J.: Prentice-Hall, 1984.
Dyfyniad MLADooley, David. Social Research Methods. Prentice-Hall, 1984.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.