The first paper analysed data from asteroids in the main belt between Mars and Jupiter and found that a group of asteroids known as the Massalia family appears similar to the meteorites found on Earth.
Computer modelling of their data showed that an impact event broke up an asteroid 450 million years ago creating the Massalia family. The second paper goes on to show that the current influx of meteorites to Earth was likely caused by three more recent breakups of asteroids larger than 30km in diameter and occurred between 5.8 and 40 million years ago in the Massalia, Karin, and Koronis asteroid families.