https://etd.repository.ugm.ac.id/penelitian/detail/544442012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/547372012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/557202012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/560542012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/565942012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/569322012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/570652012never1.0https://etd.repository.ugm.ac.id/penelitian/detail/571012012never1.0