PERSON@1 W. , Vokrouhlický D. , Nesvorný D. -LRB- NUMBER@1 -RRB- An asteroid breakup NUMBER@2 Myr ago as the probable source of the K/T impactor .

PERSON@2 , Vokrouhlický D Nesvorný D. -LRB- NUMBER@1 -RRB- An asteroid breakup NUMBER@2 Myr ago as the probable source of the K/T impactor .
