1<?xml version="1.0" encoding="utf-8"?>
2<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
3  <xs:group name="name">
4    <xs:choice>
5      <xs:element name="name" type="xs:string"/>
6      <xs:sequence>
7        <xs:element name="first-name" type="xs:string"/>
8        <xs:element name="middle-name" type="xs:string" minOccurs="0"/>
9        <xs:element name="last-name" type="xs:string"/>
10      </xs:sequence>
11    </xs:choice>
12  </xs:group>
13  <xs:element name="author">
14    <xs:complexType>
15      <xs:group ref="name"/>
16    </xs:complexType>
17  </xs:element>
18</xs:schema>
19