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<td><strong>OCP</strong></td>
<td><a href="http://www.objectmentor.com/resources/articles/ocp.pdf" target="_blank">The Open Closed Principle</a></td>
<td><em>You should be able to extend a classes behavior, without modifying it.</em></td>
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<td><strong>LSP</strong></td>
<td><a href="http://www.objectmentor.com/resources/articles/lsp.pdf" target="_blank">The Liskov Substitution Principle</a></td>
<td><em>Derived classes must be substitutable for their base classes.</em></td>
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<td><stro