?url_ver=Z39.88-2004&rft_id=10.1016%2Fj.ijpsycho.2008.05.500&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=Emiliano&rft.aulast=Ricciardi&rft.au=Ricciardi%2C+Emiliano&rft.issn=0167-8760&rft.date=2008&rft.atitle=Cholinergic+modulation+on+brain+response+to+working+memory+as+task+difficulty+increases+in+young+and+older+subjects&rft.title=International+Journal+of+Psychophysiology&rft.issue=3&rft.pages=187+-+188&rft.volume=69&rft.genre=article