For the definition of rings and ring coverings see <br>
<i> Goetzke, K., Klein, H.-J.: Properties and Efficient Algorithmic Determination of Different Classes
    of Rings in Finite and Infinite Polyhedral Networks, <br>
    Journal of Non-Crystalline Solids, 127 (1991), 215-220</i>
<p>
<!-- or (in German) <a href=http://www.hajo1766.de/Publications/m1.ps>
    <b>here</b></a>.<br> -->

<p>
Some <a href=http://www.hajo1766.de/Ringstatistic.html>
    <b>explanations on ring statistics</b></a> are helpful for the interpretation of these statistics.<br><br>
Ring statistics for several structures can be found in <br>
<a href=http://www.hajo1766.de/rings.txt>
    <b>rings</b></a> (ring classes and symmetry operations)<br> 

<a href=http://www.hajo1766.de/nodes.txt>
    <b>node-cover</b></a> (minimal node covers)<br> 
 
<a href=http://www.hajo1766.de/edges.txt>
    <b>edge-cover</b></a> (minimal edge covers) <br>
    

If you append 'b' and SNUM (from statistics) to the address http://www.hajo1766.de/
<br>
(e.g.: http://www.hajo1766.de/b46.01.80) <br>
you get the data of the corresponding structure. <br>   
<p>