Trochim, W. M. K. (2001). Research methods knowledge base (2nd ed.). Cornell University Pub., Cornell University Campus Store.
Dyfyniad Arddull ChicagoTrochim, William M. K. Research Methods Knowledge Base. 2nd ed. Ithaca, N.Y: Cornell University Pub., Cornell University Campus Store, 2001.
Dyfyniad MLATrochim, William M. K. Research Methods Knowledge Base. 2nd ed. Cornell University Pub., Cornell University Campus Store, 2001.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.