6. The computing device of claim 2 wherein the extract text component identifies a dominant reference node for each reference explanatory text node.
6. The computing device of claim 2 wherein the extract text component identifies a dominant reference node for each reference explanatory text node. 7. The computing device of claim 6 wherein a reference explanatory text node has a dominant reference node when it has only one reference node that is a block node with a unique subtree structure.