Cita APA (7th ed.)

Heywood, I., Cornelius, S., & Carver, S. (2003). An Introduction to Geographical Information Systems (2nd ed.). Pearson Education (Singapore) Pte. Ltd.

Cita Chicago (17th ed.)

Heywood, Ian, Sarah Cornelius, i Steve Carver. An Introduction to Geographical Information Systems. 2nd ed. Delhi: Pearson Education (Singapore) Pte. Ltd, 2003.

Cita MLA (9th ed.)

Heywood, Ian, et al. An Introduction to Geographical Information Systems. 2nd ed. Pearson Education (Singapore) Pte. Ltd, 2003.