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Lua i Stíl Chicago (17ú heag.).Lo, C. P., agus Albert K. W. .Yeung. Concepts and Techniques of Geographic Information Systems. 2nd ed. .Upper Saddle River, NJ: Pearson Prentice Hall, 2007.
Lua MLA (9ú heag.).Lo, C. P., agus Albert K. W. .Yeung. Concepts and Techniques of Geographic Information Systems. 2nd ed. Pearson Prentice Hall, 2007.
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