DTD

<!ELEMENT zamestnanci (zamestnanec+)>
<!ELEMENT zamestnanec (jmeno, prijmeni, email+, 
                       plat?, narozen)>
<!ELEMENT jmeno       (#PCDATA)>
<!ELEMENT prijmeni    (#PCDATA)>
<!ELEMENT email       (#PCDATA)>
<!ELEMENT plat        (#PCDATA)>
<!ELEMENT narozen     (#PCDATA)>
<!ATTLIST zamestnanec
          id     CDATA #REQUIRED>