Can you explain me the algorithm to rebuild the references from the decomposed parts of it?

[FernandoDurier]

Can you please explain to me how to rebuild the complete reference?

This is a XML fragment as an example:

<ref id="ref1">
        <mixed-citation>
          <string-name>
            <surname>Barbieri</surname>
          </string-name>
          , Francesco, Saggion, Horacio,
          <year>2014</year>
          .
          <article-title>Modelling Irony in Twitter</article-title>
          .
          <source>In: Proceedings of the Student Research Workshop at the 14th Conference of the European Chapter of the Association for Computational Linguistics.</source>
        </mixed-citation>
      </ref>

And this is a screenshot from the Cermine site showing this fragment's complete reference:

How the application interface got the complete APA reference above each section of reference's fragments?