URL	Title	Id
http://digfir-published.macmillanusa.com/astro_interactive_exercise/ie_main-sequence_stars_of_different_masses.html	Chapter 1. Main-Sequence Stars of Different Masses	5139df91b11c0f114e000000
http://digfir-published.macmillanusa.com/astro_interactive_exercise/ie_main-sequence_stars_of_different_masses_dlap.xml	DLAP questions	5139df91b11c0f114e000000