<generalEntities>
  <entity name="Implies">
    <declaredIn systemId="http://jats.nlm.nih.gov/articleauthoring/1.0/mathml/mmlalias.ent"
                publicId="-//W3C//ENTITIES Aliases for MathML 2.0//EN"
                lineNumber="200"/>
      <value>⇒</value>
  </entity>
  ...
</generalEntities>