Add a few missing articles.

README.md

@@ -58,7 +58,7 @@ To get more recent PDB entries in tooltips use --entries-idx=/.../entries.idx
 
 https://project-gemmi.github.io/pdb-stats/tags.html
 
-Similarly, for COD:
+Similarly, for the COD:
 
     $ gemmi tags --full path/to/cod/cif/ > cod-cif-tags.tsv
     $ gemmi tags --full --glob='*.hkl' path/to/cod/hkl/ > cod-hkl-tags.tsv

cod-tags.html

@@ -126,7 +126,7 @@ <h2 id="sf">HKL Files</h2>
  <a href="https://project-gemmi.github.io/">project GEMMI</a>.
  Uses <a href="https://d3js.org/">d3.js</a>
  and <a href="http://tristen.ca/tablesort/demo/">tablesort</a>.
- Data was extracted from COD on 2021-04-23.
+ Data was extracted from the COD on 2021-04-23.
  <p><b><a href="https://github.com/project-gemmi/pdb-stats">
  Source code and info...</a></b>
 </div>

index.html

@@ -44,7 +44,7 @@ <h1>Visualizations and statistics<br>based on the PDB data</h1>
 <li><a href="tags.html"><img src="thumbs/tags.png" alt="">
 <span class="h2">PDBx/mmCIF tags</span></a>
 A table that shows which tags are actually in use.
-<br>And <a href="cod-tags.html">here is a similar table for COD</a>.
+<br>And <a href="cod-tags.html">here is a similar table for the COD</a>.
 
 <li><a href="residues.html"><img src="thumbs/residue.png" alt="">
 <span class="h2">Frequency of chemical components</span></a>