<a href="https://en.wikisource.org/wiki/The_Direction_of_Force_and_Acceleration" class="extiw" title="s:The Direction of Force and Acceleration">s:The Direction of Force and Acceleration</a>
<bdi><a href="https://en.wikipedia.org/wiki/en:Richard_C._Tolman" class="extiw" title="w:en:Richard C. Tolman"><span title="American physicist (1881-1948)">Richard C. Tolman</span></a>
</bdi>
1911
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