?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.au=Harnad%2C+Stevan&rft.aulast=Harnad&rft.aufirst=Stevan&rft.date=April+1969&rft.title=The+effects+of+fixation%2C+attention%2C+and+report+on+the+frequency+and+duration+of+visual+disappearances&rft.inst=McGill+University