style:style_letter

<xsd:element name="style_letter">
  <xsd:simpleType>
    <xsd:restriction base="xsd:string">
      <xsd:minLength value="1"/>
      <xsd:maxLength value="1"/>
      <xsd:pattern value="[A-Z ]"/>
    </xsd:restriction>
  </xsd:simpleType>
</xsd:element>