https://etd.repository.ugm.ac.id/penelitian/detail/1501112014never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1501872014never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1502252014never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1503702014never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1503742014never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1504182014never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1505972014never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1506822014never1.0