13. An apparatus according to claim 12 also comprising a document merger, operative to create at least one target document based on the first and second documents, the first and second lists, and the edit data.
13. An apparatus according to claim 12 also comprising a document merger, operative to create at least one target document based on the first and second documents, the first and second lists, and the edit data. 17. An apparatus according to claim 13 comprising a comparison visualizer operative to present a view of at least one target document comprising a plurality of layer views, a layer view comprising pixels rendered from a plurality of graphic elements associated with a layer view, the visibility of a layer view being separately controllable.