Giuseppe Longo, 18 - The Tunguska event (PDF), in Peter T. Bobrowsky e Hans Rickman (a cura di), Comet/Asteroid Impacts and Human Society, An Interdisciplinary Approach, Berlin Heidelberg New York, Springer-Verlag, 2007, pp. 303–330, ISBN3-540-32709-6. URL consultato il 10 marzo 2016.