<!ELEMENT features (category+)> 

<!ELEMENT category (feature|category)*>
<!ATTLIST category name CDATA #REQUIRED > 

<!ELEMENT feature (summary?,responsible*)> 
<!ATTLIST feature status (inprogress|todo|done) "todo"
                  target CDATA #REQUIRED>

<!ELEMENT responsible EMPTY> 
<!ATTLIST responsible name CDATA #IMPLIED
                      email CDATA #IMPLIED>

<!ELEMENT summary (#PCDATA|i|a|b|em|strong)*> 

<!ELEMENT i (#PCDATA)>
<!ELEMENT b (#PCDATA)>
<!ELEMENT em (#PCDATA)>
<!ELEMENT strong (#PCDATA)>

<!ELEMENT a (#PCDATA)>
<!ATTLIST a href CDATA #IMPLIED>
<!ATTLIST a title CDATA #IMPLIED>