https://etd.repository.ugm.ac.id/penelitian/detail/2715122026never1.0https://etd.repository.ugm.ac.id/penelitian/detail/2715202026never1.0https://etd.repository.ugm.ac.id/penelitian/detail/2716592026never1.0https://etd.repository.ugm.ac.id/penelitian/detail/2717622026never1.0https://etd.repository.ugm.ac.id/penelitian/detail/2719812026never1.0https://etd.repository.ugm.ac.id/penelitian/detail/2720652026never1.0