Reference

	The Scientific Exploration of Mars by Fredric W. Taylor Year: 2009 Hits: 3704 Date insert: Monday, 31 December 2018
	The Southern Sky: A Practical Guide to Astronomy by David Reidy, Ken Wallace Year: 1988 Hits: 3184 Date insert: Monday, 31 December 2018
	THE UNIVERSE AND BEYOND by Alan Dyer, Jane A. Green Year: 2004 Hits: 1829 Date insert: Monday, 31 December 2018
	The Universe from your Backyard: A Guide to Deep Sky Objects from ASTRONOMY Magazine by David J. Eicher Year: 1988 Hits: 2913 Date insert: Monday, 31 December 2018
	The Universe of Galaxies: Readings from Scientific American by Paul W. Hodge Year: 1984 Hits: 2907 Date insert: Monday, 31 December 2018