?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aulast=Bryson&rft.au=Bryson%2C+A&rft.aufirst=A&rft.atitle=Causal+effects+of+an+absent+crowd+on+performances+and+refereeing+decisions+during+Covid-19&rft.title=Economics+Letters&rft.volume=198&rft.date=January+2021&rft.genre=article