title: CrossRef API Tracing DOI Citations
body: <p>I'm using the <code>habanero</code> library to retrieve citation information given a DOI.  I've hit a road block when trying to retrieve information about the works citing a given DOI.  For instance, </p>
  
  <pre><code>from habanero import counts
  c = counts.citation_count(doi = {DOI})
  </code></pre>
  
  <p>will give me the number of works that cited a DOI.  Unfortunately, the DOI's I'm interested in are associated with data sets, so these counts are almost always going to be 1.  What I really need is to count the citations of the work that references the DOI. For example, something like this:</p>
  
  <pre><code>from habanero import CrossRef
  cr = CrossRef()
  work = cr.works(ids = {DOI})
  work['message']['references_count']
  
  # what I'm really looking for is something like the following line
  work['message']['references_dois']
  </code></pre>
  
  <p>I've been digging through the CrossRef documentation and I haven't been able to find anything that can help me achieve this.  </p>
  
  <p>Has anyone solved a similar problem?</p>