https://etd.repository.ugm.ac.id/penelitian/detail/946892016never1.0https://etd.repository.ugm.ac.id/penelitian/detail/962282016never1.0https://etd.repository.ugm.ac.id/penelitian/detail/978942016never1.0https://etd.repository.ugm.ac.id/penelitian/detail/981362016never1.0https://etd.repository.ugm.ac.id/penelitian/detail/982352016never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1025212016never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1031932016never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1067432016never1.0