%0 Journal Article %A P. E. Hart, N. J. Nilsson, and B. Raphael %T A formal basis for the heuristic determination of minimum cost paths %B IEEE Transactions on Systems, Science, and Cybernetics %P 100-107 %V SSC-4 %D 1968 %N 2 %U http://www.ai.sri.com/pubs/files/834.pdf
