The Knight's Tour Example given in Siek, Lee and Lumsdaine's book on the BGL will not compile due to a cyclical dependency between knight_adjacency_iterator and knights_tour_graph. Would someone help me to resolve this? This is the only implicit graph example given in the text and I would very much like to learn from it. The text does not give a complete program, only a subset. I was unable to find a complete listing anywhere and have attached a version typed by myself to this email. Thank you, Brian Troutwine ps. I would appreciate pointers to further (ideally functioning) examples of implicit graphs in the BGL. The A-Star search documentation notes its usefulness for them but fails to provide any functional example of running the algorithm over such a graph.