Greig, B. (1985). Halley's comet. Writers Press.
Cita Chicago (17th ed.)Greig, Brian. Halley's Comet. Diamond Creek, Vic.: Writers Press, 1985.
Cita MLA (8th ed.)Greig, Brian. Halley's Comet. Writers Press, 1985.
Atenció: Aquestes cites poden no estar 100% correctes.