URL	Title	Id
http://digfir-published.macmillanusa.com/astro_interactive_exercise/ie_an_explanation_of_superluminal_motion.html	Chapter 1. An Explanation of Superluminal Motion	51413969b11c0f181b00000a
http://digfir-published.macmillanusa.com/astro_interactive_exercise/ie_an_explanation_of_superluminal_motion_dlap.xml	DLAP questions	51413969b11c0f181b00000a