1. Aronoff, S. 1991. Geographical Information Systems: a Management Perspective. WDl Publications, Ottawa, p. 294
2. Ballard, D.H., Brown, C.M., 1982. Computer Vision. Prentice-Hall, New York, p. 523
3. Bonham-Carter, G.F., 1994. Geographic Information Systems for Geoscientists: Modelling with GIS. Pergamon, Oxford, p. 398
4. Distance transformations in arbitrary dimensions;Borgefors;Computer Vision, Graphics, and Image Processing,1984
5. Burrough, P.A., 1986. Principles of Geographical Information Systems for Land Resources Assessment. University Press, Oxford, p. 193