?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=Jenny&rft.aulast=Houssart&rft.au=Houssart%2C+Jenny&rft.date=June+2007&rft.atitle=Investigating+Variability+in+Classroom+Performance+amongst+Children+Exhibiting+Difficulties+with+Early+Arithmetic&rft.pages=83-97&rft.issn=0267-1611&rft.title=Educational+and+Child+Psychology&rft.volume=24&rft.issue=2&rft.genre=article