?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aulast=Lu&rft.aufirst=W&rft.au=Lu%2C+W&rft.atitle=Comparing+socio-economic+inequalities+in+healthy+ageing+in+the+United+States+of+America%2C+England%2C+China+and+Japan%3A+evidence+from+four+longitudinal+studies+of+ageing&rft.title=Ageing+%26+Society&rft.date=9+December+2019&rft.genre=article