http://digfir-published.macmillanusa.com/hm_custom_osu/hmosu structure of solids w13.html\tChapter 13. Structure of Solids
\t50d33aabb11c0f1522000000
http://digfir-published.macmillanusa.com/hm_custom_osu/hmosu structure of solids w13_dlap.xml\tDLAP questions\t50d33aabb11c0f1522000000