?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Sigmund%2C+K.&rft.aulast=Sigmund&rft.aufirst=K.&rft.date=1995&rft.issn=1866-7414&rft.atitle=A+philosopher's+mathematician%3A+Hans+Hahn+and+the+Vienna+Circle&rft.title=Mathematical+Intelligencer&rft.pages=16-29&rft.genre=article