1. Holland, J: Adaptation in Natural and Artificial Systems. University of Michigan Press (1975)
2. Goldberg, D.: Genetic Algorithms in Search, Optimization and Machine Learning. Addison-Wesley, Reading (1989)
3. Hopfield, J., Tank, D.: Neural computation of decisions in optimization problems. Biological Cybernetics 52, 141–152 (1985)
4. Hakimi, S.: Optimum locations of switching centers and absolute centers and medians of to graph. Operations Research 12, 450–459 (1964)
5. Kariv, O., Hakimi, S.: An algorithmic approach to network location problem. part 2: The p-median. SIAM J. Appl. Math. 37, 539–560 (1979)