Cita APA (7th ed.)

Heywood, I., Cornelius, S., & Carver, S. (2011). An introduction to geographical information systems (4a. ed.). Pearson Education Limited.

Cita Chicago (17th ed.)

Heywood, Ian, Sarah Cornelius, i Steve Carver. An Introduction to Geographical Information Systems. 4a. ed. Essex: Pearson Education Limited, 2011.

Cita MLA (9th ed.)

Heywood, Ian, et al. An Introduction to Geographical Information Systems. 4a. ed. Pearson Education Limited, 2011.