https://etd.repository.ugm.ac.id/penelitian/detail/109302000never1.0https://etd.repository.ugm.ac.id/penelitian/detail/109512000never1.0https://etd.repository.ugm.ac.id/penelitian/detail/109522000never1.0https://etd.repository.ugm.ac.id/penelitian/detail/117022000never1.0https://etd.repository.ugm.ac.id/penelitian/detail/117232000never1.0https://etd.repository.ugm.ac.id/penelitian/detail/117242000never1.0