https://etd.repository.ugm.ac.id/penelitian/detail/408932009never1.0https://etd.repository.ugm.ac.id/penelitian/detail/429882009never1.0https://etd.repository.ugm.ac.id/penelitian/detail/429892009never1.0https://etd.repository.ugm.ac.id/penelitian/detail/429902009never1.0https://etd.repository.ugm.ac.id/penelitian/detail/429912009never1.0https://etd.repository.ugm.ac.id/penelitian/detail/429922009never1.0https://etd.repository.ugm.ac.id/penelitian/detail/429932009never1.0