https://etd.repository.ugm.ac.id/penelitian/detail/130292003never1.0https://etd.repository.ugm.ac.id/penelitian/detail/130302003never1.0https://etd.repository.ugm.ac.id/penelitian/detail/130362003never1.0https://etd.repository.ugm.ac.id/penelitian/detail/130372003never1.0https://etd.repository.ugm.ac.id/penelitian/detail/130382003never1.0https://etd.repository.ugm.ac.id/penelitian/detail/130392003never1.0https://etd.repository.ugm.ac.id/penelitian/detail/130622003never1.0