APA-referens

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

Chicago-stil citat

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

MLA-referens

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