+<indexterm id='idxcongressuscopyrighttermsextendedby2' class='startofrange'><primary>Congress, U.S.</primary><secondary>copyright terms extended by</secondary></indexterm>
+<indexterm id='idxcopyrightdurationof6' class='startofrange'><primary>copyright</primary><secondary>duration of</secondary></indexterm>
+<indexterm id='idxcopyrightlawtermextensionsin2' class='startofrange'><primary>copyright law</primary><secondary>term extensions in</secondary></indexterm>
+<indexterm><primary>Frost, Robert</primary></indexterm>
+<indexterm><primary>New Hampshire (Frost)</primary></indexterm>
+<indexterm><primary>patents</primary><secondary>in public domain</secondary></indexterm>
+<indexterm id='idxpatentsfuturepatentsvsfuturecopyrightsin' class='startofrange'><primary>patents</primary><secondary>future patents vs. future copyrights in</secondary></indexterm>