https://etd.repository.ugm.ac.id/penelitian/detail/787932015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/793102015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/793272015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/794362015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/826232015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/828482015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/829752015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/860062015never1.0https://etd.repository.ugm.ac.id/penelitian/detail/912262015never1.0