Zemke, R. (2001). E-service. McGraw-Hill.
Dyfyniad Arddull ChicagoZemke, Ron. E-service. McGraw-Hill, 2001.
Dyfyniad MLAZemke, Ron. E-service. McGraw-Hill, 2001.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.
Zemke, R. (2001). E-service. McGraw-Hill.
Dyfyniad Arddull ChicagoZemke, Ron. E-service. McGraw-Hill, 2001.
Dyfyniad MLAZemke, Ron. E-service. McGraw-Hill, 2001.