"r-pr">#&gt;</span> 1       http://www.psych.nyu.edu/adolph/</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 2                                   &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 3                                   &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 4                                   &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 5  http://www.psych.nyu.edu/vouloumanos/</span>
<span class="r