http://digfir-published.macmillanusa.com/gls_animated_graph/gls_4_14.html\tChapter 1. eFigure 4.14 \t52322756757a2e3011000000 http://digfir-published.macmillanusa.com/gls_animated_graph/gls_4_14_dlap.xml\tDLAP questions\t52322756757a2e3011000000