?url_ver=Z39.88-2004&rft_id=doi%3A10.33774%2Fcoe-2021-9w3gs&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Crespo+%C3%81lvarez%2C+Jorge&rft.aufirst=Jorge&rft.aulast=Crespo+%C3%81lvarez&rft.atitle=Orbits+Theory.+A+Complete+Proof+of+the+Collatz+Conjecture&rft.date=Diciembre+2021&rft.title=Cambridge+Open+Engage&rft.genre=article