Macleod, N.; Rawson, P. F.; Forey, P. L.; Banner, F. T.; Boudagher-Fadel, M. K.; Bown, P. R.; Burnett, J. A.; Chambers, P.; Culver, S.; Evans, S. E.; Jeffery, C.; Kaminski, M. A.; Lord, A. R.; Milner, A. C.; Milner, A. R.; Morris, N.; Owen, E.; Rosen, B. R.; Smith, A. B.; Taylor, P. D.; Urquhart, E.; Young, J. R. (aprilie 1997). „The Cretaceous-Tertiary biotic transition”. Journal of the Geological Society. 154 (2): 265–292. Bibcode:1997JGSoc.154..265M. doi:10.1144/gsjgs.154.2.0265.
Sackmann, I.-J.; Boothroyd, A. I.; Kraemer, K. E. (). „Our Sun. III. Present and Future”. Astrophysical Journal. 418: 457–68. Bibcode:1993ApJ...418..457S. doi:10.1086/173407.
Macleod, N.; Rawson, P. F.; Forey, P. L.; Banner, F. T.; Boudagher-Fadel, M. K.; Bown, P. R.; Burnett, J. A.; Chambers, P.; Culver, S.; Evans, S. E.; Jeffery, C.; Kaminski, M. A.; Lord, A. R.; Milner, A. C.; Milner, A. R.; Morris, N.; Owen, E.; Rosen, B. R.; Smith, A. B.; Taylor, P. D.; Urquhart, E.; Young, J. R. (aprilie 1997). „The Cretaceous-Tertiary biotic transition”. Journal of the Geological Society. 154 (2): 265–292. Bibcode:1997JGSoc.154..265M. doi:10.1144/gsjgs.154.2.0265.
Sackmann, I.-J.; Boothroyd, A. I.; Kraemer, K. E. (). „Our Sun. III. Present and Future”. Astrophysical Journal. 418: 457–68. Bibcode:1993ApJ...418..457S. doi:10.1086/173407.
J. T. Wickramasinghe & W. N. Napier, Impact cratering and the Oort Cloud, Monthly Notices of the Royal Astronomical Society, 387, 153-157 (2008), arXiv:0803.2492 (astro-ph) Voir en ligne.