Use Case Tree: DTD

<!DOCTYPE book [
  <!ELEMENT book (title, author+, section+)>
  <!ELEMENT title (#PCDATA)>
  <!ELEMENT author (#PCDATA)>
  <!ELEMENT section (title, (p | figure | section)* )>
  <!ELEMENT p (#PCDATA)>
  <!ELEMENT figure (title, image)>
  <!ATTLIST image
       source  CDATA  #REQUIRED > 
]>