1. Navigational techniques to improve the display of large two-dimensional spaces
2. Bertin J. (1983). Semiology of graphics diagrams networks maps. University of Wisconsin Press. Bertin J. (1983). Semiology of graphics diagrams networks maps. University of Wisconsin Press.
3. Busha C.H. Harter S.P. (1980). Research methods in librarianship: Techniques and interpretation. New York: Academic Press. Busha C.H. Harter S.P. (1980). Research methods in librarianship: Techniques and interpretation. New York: Academic Press.
4. Ellson J. Gansner E. Koutsofios E. Mocenigo J. North S. Woodhull G. (2005). Graphviz open source graph drawing software. http://www.research.att.com/sw/tools/graphviz/ Ellson J. Gansner E. Koutsofios E. Mocenigo J. North S. Woodhull G. (2005). Graphviz open source graph drawing software. http://www.research.att.com/sw/tools/graphviz/