Steel, D. (1995). Rogue asteroids and doomsday comets: The search for the million megaton menace that threatens life on earth. Wiley.
Chicago-viite (17. p.)Steel, Duncan. Rogue Asteroids and Doomsday Comets: The Search for the Million Megaton Menace That Threatens Life on Earth. New York: Wiley, 1995.
MLA-viite (9. p.)Steel, Duncan. Rogue Asteroids and Doomsday Comets: The Search for the Million Megaton Menace That Threatens Life on Earth. Wiley, 1995.
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