| http://digfir-published.macmillanusa.com/calc_tutorial/calc_tutorial_15_4_021.html | Chapter 1. calc_tutorial_15_4_021
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| http://digfir-published.macmillanusa.com/calc_tutorial/calc_tutorial_15_4_021_dlap.xml | DLAP questions | 50c242c2b11c0fc546000000 |