https://etd.repository.ugm.ac.id/penelitian/detail/277132005never1.0https://etd.repository.ugm.ac.id/penelitian/detail/277462005never1.0https://etd.repository.ugm.ac.id/penelitian/detail/284362005never1.0https://etd.repository.ugm.ac.id/penelitian/detail/284372005never1.0https://etd.repository.ugm.ac.id/penelitian/detail/286962005never1.0https://etd.repository.ugm.ac.id/penelitian/detail/293512005never1.0https://etd.repository.ugm.ac.id/penelitian/detail/295682005never1.0