Dyfyniad APA

Longley, P. (2015). Geographic information science & systems (4th ed.). Wiley.

Dyfyniad Arddull Chicago

Longley, Paul. Geographic Information Science & Systems. 4th ed. Hoboken, NJ: Wiley, 2015.

Dyfyniad MLA

Longley, Paul. Geographic Information Science & Systems. 4th ed. Wiley, 2015.

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