?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.aulast=Purwastri&rft.au=Purwastri%2C+Pamela+Yeni&rft.aufirst=Pamela+Yeni&rft.title=USING+COOPERATIVE+GAMES+TO+IMPROVE+THE+SPEAKING+SKILLS+OF+GRADE+VIII+E+STUDENTS+OF+SMP+NEGERI+2+PIYUNGAN+IN+THE+ACADEMIC+YEAR+OF+2014%2F2015&rft.date=24+October+2014&rft.inst=Universitas+Negeri+Yogyakarta&rft.degree=S1