1. Wiley Series in Probability and Mathematical Statistics;J.A. Hartigan,1975
2. Cormen, T.H., Leiserson, C.E., Rivest, R.L., Stein, C.: Introduction to Algorithms, 2nd edn. MIT Press and McGraw-Hill (2001) ISBN 0-262-03293-7, Section 34.2: Polynomial-time verification, pp. 979–983, Cambridge, Massachusetts
3. Bremner, D., Demaine, E., Erickson, J., Iacono, J., Langerman, S., Morin, P., Toussaint, G.: Output-sensitive algorithms for computing nearest-neighbor decision boundaries. Discrete and Computational Geometry 33(4), 593–604 (2005)
4. Ester, M., Kriegel, H.-P., Sander, J., Xu, X.: A density-based algorithm for discovering clusters in large spatial databases with noise. In: Proceedings of the Second International Conference on Knowledge Discovery and Data Mining (KDD 1996), pp. 226–231. AAAI Press, Menlo Park (1996) ISBN 1-57735-004-9
5. Buttenfield, B.P.: Looking Forward: Geographic Information Services and Libraries in the Future. In: Cartography and Geographic Information Society, American Congress on Surveying and Mapping (ACSM), vol. 25(3), pp. 161–171 (1998)