<?xml version="1.0" encoding="UTF-8"?>
<!-- 
    DTR1 BL - Boolean
    Status: draft
-->
<rule xmlns="http://purl.oclc.org/dsdl/schematron"
      abstract="true"
      id="BL"
      see="https://art-decor.org/mediawiki/index.php?title=DTr1_BL">
    <extends rule="ANY"/>
    <!--
    <assert test="@nullFlavor or (not(@nullFlavor) and @value)">Datatype BL: value or null</assert>
    -->
</rule>
