entry</span><span class=special>,</span>
  <span class=identifier>indexed_by</span><span class=special>&lt;</span>
    <span class=comment>// non-unique as some subscribers might have more than one number</span>
    <span class=identifier>ordered_non_unique</span><span class=special>&lt;</span> 
      <span class=identifier>composite_key</span><span class=special>&lt;</span>
        <span class=identifier>phonebook_entry</span><span class=special>,</span>
        <span class=identifier>member</span><span cl