https://etd.repository.ugm.ac.id/penelitian/detail/541152012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/541162012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/547652012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/551672012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/553852012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/560982012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/563332012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/563352012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/584262012never1.0