A manual first sift was then carried out based on a reading of the reference title, and if that proved inconclusive, the abstract/summary to identify which references were relevant and which were not.
Yna, cynhaliwyd ymarfer hidlo cyntaf â llaw yn seiliedig ar ddarllen teitl y cyfeiriad, ac os oedd hwnnw'n amhenodol, y crynodeb er mwyn nodi p'un a oedd cyfeiriadau yn berthnasol ai peidio.