Asidu wen ehay standarized paper sheets d karti tan idnay nen daɣ biraw tan aɣna nen s alasal s immik wan hierarchical index (wa immasan isalan daɣ alɣalim n almasdar tan ajjotnen) d sarwis wan asidu n isalan win mamala (ehak in alwazab isistanan iktab nen s asigbar n isalan n index cards)