<?xml version="1.0" encoding="utf-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema"
        targetNamespace="http://www.language-archives.org/OLAC/0.4/">

  <annotation>
    <documentation>
      OLAC Schema for dates, Steven Bird, 5/7/01
      ** this is XML DTF without times, but with year-ranges
      Refinements are from DC Qualifiers
      http://dublincore.org/documents/2000/07/11/dcmes-qualifiers/
      A possibility for date ranges is the DCSV method described in
      http://dublincore.org/documents/dcmi-period/
    </documentation>
  </annotation>

  <simpleType name="OLAC-Date-Refine">
    <restriction base="string">
      <enumeration value="created"/>
      <enumeration value="valid"/>
      <enumeration value="available"/>
      <enumeration value="issued"/>
      <enumeration value="modified"/>
    </restriction>
  </simpleType>
  
  <simpleType name="OLAC-Date-Code">  <!-- weak definition -->
    <restriction base="string">
      <pattern value="[0-9][0-9][0-9][0-9](-[0-9][0-9](-?[0-9][0-9])?)?"/>
    </restriction>
  </simpleType>
  
</schema>
  
