https://etd.repository.ugm.ac.id/penelitian/detail/1581052018never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1588112018never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1629182018never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1630072018never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1635242018never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1637932018never1.0https://etd.repository.ugm.ac.id/penelitian/detail/1670092018never1.0