?url_ver=Z39.88-2004&rft_id=10.1155%2F2021%2F8791620&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=G.E.&rft.aulast=Mustafa+Abro&rft.au=Mustafa+Abro%2C+G.E.&rft.volume=2021&rft.issn=1024123X&rft.atitle=Performance+Evaluation+of+Different+Control+Methods+for+an+Underactuated+Quadrotor+Unmanned+Aerial+Vehicle+(QUAV)+with+Position+Estimator+and+Disturbance+Observer&rft.title=Mathematical+Problems+in+Engineering&rft.date=2021&rft.genre=article