Hello, I've been trying to use the write_graphviz function in BGL, and I've noticed that it appears to be sensitive to the type of VertexList used in the graph. adjacency_lists using a boost::vecS produce vertex indices in integer form like: graph G { 0[label="0"]; 1[label="1"]; 0--1 [label="2.8"]; } but the same code backed by boost::listS seems to not dereference completely: graph G { 0x80545f0[label="10"]; 0x8054608[label="11"]; 0x80545f0--0x8054608 [label="2.8"]; } dot doesn't like this. I notice that write_graphviz dereferences boost::graph_traits<Graph>::vertex_iterator to print the vertex. Are the listS and vecS *operators different somehow? The vector backed adjacency_list also seems to be automagically setting the vertex_index property to the actual index of the vertex in the storage vector instead of the value given in add_vertex(). My question is: Is this the expected behavior for these classes or some problem I've managed to create on my own? Thanks, Solomon