Dyfyniad APA

Gorr, W. L., & Wilpen L. Gorr; Kristen S. Kurland. (2007). Learning and using geographic information systems: ArcGIS edition. Boston, Mass: Thomson Course Technology.

Dyfyniad Arddull Chicago

Gorr, Wilpen L., và Wilpen L. Gorr; Kristen S. Kurland. Learning and Using Geographic Information Systems: ArcGIS Edition. Boston, Mass: Thomson Course Technology, 2007.

Dyfyniad MLA

Gorr, Wilpen L., và Wilpen L. Gorr; Kristen S. Kurland. Learning and Using Geographic Information Systems: ArcGIS Edition. Boston, Mass: Thomson Course Technology, 2007.

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