Far Centaurus
... that Robert Forward invoked van Vogt's short story "Far Centaurus" when discussing the problem of interstellar travel?
... that <a class="mw-redirect" href="./Robert_Forward" id="mwBDo" rel="mw:WikiLink" title="Robert Forward">Robert Forward</a> invoked <a href="./A._E._van_Vogt" id="mwBDs" rel="mw:WikiLink" title="A. E. van Vogt">van Vogt's</a> short story "<b id="mwBDw"><a href="./Far_Centaurus" id="mwBD0" rel="mw:WikiLink" title="Far Centaurus">Far Centaurus</a></b>" when discussing the problem of <a href="./Interstellar_travel" id="mwBD4" rel="mw:WikiLink" title="Interstellar travel">interstellar travel</a>?