<triple>
  <boolean>
    <value>or</value>
  </boolean>
  <leftOperand>
    <searchClause>
      <index>cql.serverChoice</index>
      <relation>
        <value>=</value>
      </relation>
      <term>a</term>
    </searchClause>
  </leftOperand>
  <rightOperand>
    <searchClause>
      <index>cql.serverChoice</index>
      <relation>
        <value>=</value>
      </relation>
      <term>b</term>
    </searchClause>
  </rightOperand>
  <sortKeys>
    <key>
      <index>title</index>
        <modifiers>
          <modifier>
            <type>ascending</type>
          </modifier>
        </modifiers>
    </key>
    <key>
      <index>author</index>
    </key>
  </sortKeys>
</triple>
