Laurinni, R., & Thompson, D. Fundamentals of spatial Information systems.
Lua i Stíl Chicago (17ú heag.)Laurinni, Robert, agus Dereck Thompson. Fundamentals of Spatial Information Systems.
Lua MLA (8ú heag.)Laurinni, Robert, agus Dereck Thompson. Fundamentals of Spatial Information Systems.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.