https://etd.repository.ugm.ac.id/penelitian/detail/507072011never1.0https://etd.repository.ugm.ac.id/penelitian/detail/507572011never1.0https://etd.repository.ugm.ac.id/penelitian/detail/507872011never1.0https://etd.repository.ugm.ac.id/penelitian/detail/517542011never1.0https://etd.repository.ugm.ac.id/penelitian/detail/518292011never1.0https://etd.repository.ugm.ac.id/penelitian/detail/518552011never1.0https://etd.repository.ugm.ac.id/penelitian/detail/528992011never1.0https://etd.repository.ugm.ac.id/penelitian/detail/531722011never1.0