Mirror: <a href="http:&#x2F;&#x2F;super-memory.com&#x2F;articles&#x2F;sleep.htm" rel="nofollow">http:&#x2F;&#x2F;super-memory.com&#x2F;articles&#x2F;sleep.htm</a><p>Past discussion: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=5244619" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=5244619</a><p>(Maybe not an exact mirror, but substantially the same article.)