<!ELEMENT ROOT (A,B) >
              

<element name="ROOT">
 <complexType content="elementOnly">
  <element ref="t:A">
  <element ref="t:B">
 </complexType>
<element>
              

<!ELEMENT ROOT (A|B) >
              

<element name="ROOT">
 <complexType content="elementOnly">
  <choice>
   <element ref="t:A">
   <element ref="t:B">
  </choice>
 </complexType>
<element>
              

<!ELEMENT ROOT (A|(B,C)) >
              

<element name="ROOT">
 <complexType content="elementOnly">
  <choice>
   <element ref="t:A">
   <sequence>
    <element ref="t:B">
    <element ref="t:C">
   </sequence>
  </choice>
 </complexType>
<element>
              

<!ELEMENT ROOT (A?,B+,C*) >
              

<element name="ROOT">
 <complexType content="elementOnly">
  <element ref="t:A" minOccurs="0">
  <element ref="t:B" maxOccurs="unbounded">
  <element ref="t:C" minOccurs="0" maxOccurs="unbounded">
 </complexType>
<element>