?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.aufirst=Marlindawati&rft.aulast=Marlindawati&rft.au=Marlindawati%2C+Marlindawati&rft.inst=Universitas+Negeri+Padang&rft.title=Students%E2%80%99+Ability+in+Using+and+Understanding+the+Present+Perfect+Tense%3A+A+Descriptive+Study+at+SMP+31+Padang&rft.degree=Bachelor%2FSkripsi&rft.date=2008