<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="exercise"
    targetNamespace="http://ufcpp.net/study/document"
    elementFormDefault="qualified"
    xmlns="http://ufcpp.net/study/document"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
>
  <xs:include id="division" schemaLocation="division.xsd"/>

  <xs:element name="exercise">
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element minOccurs="1" maxOccurs="1" name="question" type="division_type"/>
        <xs:element minOccurs="1" maxOccurs="unbounded" name="answer" type="division_type"/>
      </xs:choice>
      <xs:attribute name="id" type="xs:string"/>
    </xs:complexType>
  </xs:element>

  <xs:element name="refex">
    <xs:complexType>
      <xs:attribute name="doc" type="xs:string" use="required"/>
      <xs:attribute name="pos" type="xs:int" use="required"/>
    </xs:complexType>
  </xs:element>

</xs:schema>