<!entity % EMail "EMail"> <!element EMail - o (sender, receiver,contents)> <!element sender o o (person) > <!element receiver o o (person)+ > <!element person o o ( distributionlist |(firstname, middlename?, lastname)) > <!element (firstname, middlename, lastname) o o (#PCDATA)> <!element distributionlist o o (#PCDATA)> <!element contents o o (#PCDATA)>