1<!ENTITY % b SYSTEM "http://example.org/b/b.dtd"> 2%b; 3<!ENTITY % c SYSTEM "http://example.org/c/c.dtd"> 4%c; 5<!ENTITY % a SYSTEM "http://example.org/a/a.dtd"> 6%a; 7<!ELEMENT bca (b, c, a)> 8