?url_ver=Z39.88-2004&rft_id=10.1108%2FJSM-05-2020-0164&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=A.&rft.au=Hussain%2C+A.&rft.aulast=Hussain&rft.issue=3&rft.volume=36&rft.issn=08876045&rft.atitle=Videogames-as-a-service%3A+converting+freemium-+to+paying-users+through+pop-up+advertisement+value&rft.pages=398-415&rft.title=Journal+of+Services+Marketing&rft.date=2022&rft.genre=article