Origin of Einstein's famous formula

I mentioned below a new paper on E=mc² before Einstein. PhysicsWorld now reports on it:

Robert Crease, a philosopher and historian of science at Stony Brook University in New York, agrees. "Historians often say that, had there been no Einstein, the community would have converged on special relativity shortly", he says. "Events were pushing them kicking and screaming in that direction." Boughn and Rothman's work, he says, shows that Hasenöhrl was among those headed this way. ...

Did Einstein know of Hasenöhrl's work? "I can't prove it, but I am reasonably certain that Einstein must have done, and just decided to do it better", says Rothman. But failure to cite it was not inconsistent with the conventions of the time.

Yes it was inconsistent. All the other relativity papers cite their sources. Einstein is the exception. And the problem is not just that he failed to cite sources in his original paper; he gave interviews and wrote articles all his life telling how he discovered relativity, and always refused to credit his sources.