6. The computer program product of claim 3 , wherein linkage metadata instances associate at least two source documents having at least two matching source fragments.
7. The computer program product of claim 6 , wherein the operations further comprise: generating, for target fragments each having at least one linkage metadata instance, a visualization of the at least one linkage metadata instance of the target fragment to the at least two source documents including the matching source fragments associated in the at least one linkage metadata instance.