| http://digfir-published.macmillanusa.com/astro_interactive_exercise/ie_the_magnetic_fields_of_five_planets.html |
Chapter
1. The Magnetic Fields of Five Planets
| 513ab21eb11c0f605b00000c |
| http://digfir-published.macmillanusa.com/astro_interactive_exercise/ie_the_magnetic_fields_of_five_planets_dlap.xml | DLAP questions | 513ab21eb11c0f605b00000c |