Z. Michalewicz and D. B. Fogel. How to Solve It: Modern Heuristics, 2nd edition, Springer-Verlag, 2004
Artificial Intelligence: A Modern Approach (Second Edition) by Stuart Russell and Peter Norvig; Prentice Hall, 2003. ISBN 0-13-103805-2.
Different scientific papers
(slides: http://www.dbai.tuwien.ac.at/staff/musliu/ProblemSolvingAI/ )