?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Mulyono%2C+Herri&rft.aufirst=Herri&rft.aulast=Mulyono&rft.date=2021&rft.title=Heliyon&rft.volume=7&rft.atitle=The+application+of+WhatsApp+to+support+online+learning+during+the+COVID-19+pandemic+in+Indonesia&rft.issue=8&rft.genre=article