37. The computer-readable medium as recited in claim 26 , wherein the process further comprises converting the selected supplemental content item into an annotatable format if the selected supplemental content item is not in an annotatable format.
26. A non-transitory computer-readable medium having instructions executable by a computer to cause the computer to carry out a process for generating a structured electronic document, the process comprising: selecting a supplemental content item having content to be added to a structured document, wherein the supplemental content item is derived from an original content item; annotating the selected content item to derive an annotated supplemental content item; designating a unique identifier for the annotated supplemental content item; generating a reference to the annotated supplemental content item, the reference including the unique identifier; inserting the reference into a primary document to link the primary document to the annotated supplemental content item; and assembling the primary document, the supplemental content item and the annotated supplemental content item into a structured electronic document.