Linking with BGL adjacency_list_io.hpp

Hi, I'm having trouble linking code that uses adjacency_list_io.hpp. If the header is included is included in more than one compilation unit, I get "multiple definition of function" errors for the non-template functions in adjacency_list_io.hpp: std::istream& operator >> ( std::istream& in, no_property& ) and void getSubset( no_property& p, const no_property& s ) I'm sure that there is some C+ subtlety that I'm missing here, but I'm not familiar enough with the library to understand what it is. Shouldn't non-template function code be in a .cpp file to keep this sort of thing from happening? - Solomon