1.1 ! misho 1: <!DOCTYPE doc [ ! 2: <!ELEMENT doc ((a, b)| (a, c))> ! 3: <!ELEMENT a EMPTY> ! 4: <!ELEMENT b (#PCDATA)> ! 5: <!ELEMENT c (#PCDATA)> ! 6: ]> ! 7: <doc><a/><c> doc is non-deterministic </c></doc>