Hi All. I've found on Hackage site that the data graph library fgl is perfect in order to achieve my aims. I've downloaded the user guide of Martin Erwig and now I'm searching for some sample code. Where can I find some line of code using fgl library? Thanks in advance for any Ideas. Luca. _________________________________________________________________ http://clk.atdmt.com/UKM/go/195013117/direct/01/