?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Dang%2C+Duc+Hanh&rft.aulast=Dang&rft.aufirst=Duc+Hanh&rft.date=2008&rft.title=Triple+Graph+Grammars+and+OCL+for+Validating+System+Behavior&rft.genre=proceeding