5Freitag, U. 1993. Map functions In The Selected Main Theoretical Issues Facing Cartography:Report of the ICA-Working Group to Define the Main Theoretical Issues on Cartography, ed. T Kanakubo, pp 9-19. Cologne International Cartographic Association.
6Kimberling, A.J.,Buckley A. R., Muehrcke, P. C. and Muehrcke, J O.,Map use:reading, analysis interpretation, ESRI Press Academic, 2012.
