1 <!DOCTYPE doc [ 2 <!ATTLIST doc attrExtEnt ENTITY #IMPLIED> 3 <!ENTITY ent1 "Hello"> 4 <!ENTITY ent2 SYSTEM "world.txt"> 5 <!ENTITY entExt SYSTEM "earth.gif" NDATA gif> 6 <!NOTATION gif SYSTEM "viewgif.exe"> 7 ]> 8 <doc attrExtEnt="entExt"> 9 &ent1;, &ent2;! 10 </doc> 11 12 <!-- Let world.txt contain "world" (excluding the quotes) --> 13