Dyfyniad APA

Heywood, I., Cornelius, S., & Carver, S. (1998). An introduction to geographical information systems. Addison-Wesley longman.

Dyfyniad Arddull Chicago

Heywood, Ian, Sarah Cornelius, and Steve Carver. An Introduction to Geographical Information Systems. New York: Addison-Wesley longman, 1998.

Dyfyniad MLA

Heywood, Ian, et al. An Introduction to Geographical Information Systems. Addison-Wesley longman, 1998.

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