In addition to the software, many (most?) of the important papers relating to ACT-R are available for download as well.<p><a href="http:&#x2F;&#x2F;act-r.psy.cmu.edu&#x2F;publication&#x2F;" rel="nofollow">http:&#x2F;&#x2F;act-r.psy.cmu.edu&#x2F;publication&#x2F;</a><p>This is a good one: &quot;How Can The Human Mind Occur In The Physical Universe&quot;  <a href="http:&#x2F;&#x2F;act-r.psy.cmu.edu&#x2F;wordpress&#x2F;?post_type=publications&amp;p=14305" rel="nofollow">http:&#x2F;&#x2F;act-r.psy.cmu.edu&#x2F;wordpress&#x2F;?post_type=publications&amp;p...</a><p>and<p>&quot;A Spreading Activation Theory of Memory&quot; <a href="http:&#x2F;&#x2F;act-r.psy.cmu.edu&#x2F;wordpress&#x2F;?post_type=publications&amp;p=13730" rel="nofollow">http:&#x2F;&#x2F;act-r.psy.cmu.edu&#x2F;wordpress&#x2F;?post_type=publications&amp;p...</a>