Asteroid that eradicated dinosaurs not a one-off, say scientists The GuardianNadir crater: The asteroid that killed the dinosaurs was not alone BBC.com3D anatomy of the Cretaceous–Paleogene age Nadir Crater Nature.comFive-mile asteroid impact crater below Atlantic captured in 'exquisite' detail by seismic data Phys.orgTwo Asteroids, One Dinosaur Extinction: Second Crater Bolsters Double Impact Theory Gizmodo