Walter Gerlach
...that German physicist Walter Gerlach helped prove the fact that electrons spin?
...that <a href="./Germany" id="mwCiI" rel="mw:WikiLink" title="Germany">German</a> <a href="./Physicist" id="mwCiM" rel="mw:WikiLink" title="Physicist">physicist</a> <b id="mwCiQ"><a class="mw-redirect" href="./Walter_Gerlach" id="mwCiU" rel="mw:WikiLink" title="Walter Gerlach">Walter Gerlach</a></b> helped <a href="./Stern–Gerlach_experiment" id="mwCiY" rel="mw:WikiLink" title="Stern–Gerlach experiment">prove</a> the fact that <a href="./Electron" id="mwCic" rel="mw:WikiLink" title="Electron">electrons</a> <a href="./Spin_(physics)" id="mwCig" rel="mw:WikiLink" title="Spin (physics)">spin</a>?