DTD for a Mail Document

<!doctype 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)>
]>

And you thought the marked up document was ugly!