Elements with children having a minimum of one occurrence can be defined. The "+" sign is used to declare that the child element must occur once or more times inside the element.
<?xml version="1.0" standalone="yes"?> <!DOCTYPE rootelement [ <!ELEMENT rootelement (childelement+)> <!ELEMENT childelement (#PCDATA)> ]> <rootelement> <childelement>Child element.</childelement> <childelement>Child element.</childelement> </rootelement>