12. The computer program product of claim 9 , wherein the computer usable program code configured to create at least one delta document further comprises at least one of computer usable program code configured to specify within at least one “add” operation a value element comprising content to be added or computer usable program code configured to specify within at least one “remove” operation a value element comprising content to be added when the “remove” operation is interpreted with reference to an end type of source document.
9. A computer program product comprising: a computer readable medium having computer-usable program code stored thereon that expresses a change history for a markup language document, the computer program product comprising: computer usable program code configured to identify a source markup language document and a modification to the source markup language document; computer usable program code configured to create at least one delta document specifying the modification to the source markup language document, wherein the delta document is independent of the source markup language document and is coded in a different language than the source markup language document, wherein creating the delta document comprises specifying each modification to the plurality of source markup language documents, within the delta document, as an “add” operation or a “remove” operation comprising a reference to a location in the source markup language document of the plurality of source markup language documents to which each respective modification is to be applied and including, within each “add” operation and “remove” operation, a time stamp indicating when the modification was implemented; and computer usable program code configured to store the source markup language document and the delta document within a data storage device.