I might be pushing the publishing envelope here, but this Science paper was available at several locations on the web for free with no sign-in. For the time being it is now on Scribd:
Therefore, a wave of micrometer sized Datura particles may have reached Earthonly a few thousand years after the formation of the Datura cluster. Signs of this event may be found by analyzing tracers of extraterrestrial dust in deep ocean sediments and Antarctic ice cores. — Conclusion, The Break-up of a Main Belt Asteroid 450,000 years ago.