Melott, Adrian (2004). «Did a gamma-ray burst initiate the late Ordovician mass extinction?». International Journal of Astrobiology3: 55–61. doi:10.1017/S1473550404001910.
Wilson, M. A.; Palmer, T.J. (2001). «Domiciles, not predatory borings: a simpler explanation of the holes in Ordovician shells analyzed by Kaplan and Baumiller, 2000». Palaios16: 524–525. doi:10.1669/0883-1351(2001)016<0524:DNPBAS>2.0.CO;2.