found:NASA Thes.(Halley's comet. Def.: a member of the solar system with an orbit and a period of about 76 years)
found:Room, A. Dict. of astronomical names, 1988(Halley's comet: the best-known comet to the lay observer or non-astronomer, and one whose return can be confidently predicted every 76 years. See reference from Comey Halley)
found:Mitton, J. Cambridge dict. of astronomy, 2001(Halley's Comet (Comet 1P/Halley): the most famous of all periodic comets)
found:Dict. of astronomy, 2003(Halley's comet (1P/Halley): best known periodic comet)