MOESM3 of Tracking research trends and hotspots in sperm DNA fragmentation testing for the evaluation of male infertility: a scientometric analysis BaskaranSaradha AgarwalAshok Panner SelvamManesh FinelliRenata RobertKathy IovineConcetta PushparajPeter SamantaLuna HarlevAvi HenkelRalf 2019 Additional file 3: Table S1. Keywords used for each step in the Stepwise Model.