?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Dao%2C+Thi+Huong&rft.aulast=Dao&rft.aufirst=Thi+Huong&rft.date=2018&rft.issn=0218-1940&rft.atitle=Preservation+of+Class+invariants+in+refactoring+UML+models&rft.title=International+journal+of+software+engineering+and+knowledge+engineering+(IJSEKE)&rft.genre=article