The purpose of ITU-T Rec. T.410-Series | ISO/IEC 8613 is to facilitate the interchange and manipulation of documents. In the context of these Recommendations | International Standards, documents are considered to be items such as memoranda, letters, invoices, forms and reports, which may include pictures and tabular material. The content elements used within the documents may include graphic characters, raster graphics elements and geometric graphics elements, all potentially within one document. NOTE — These Recommendations | International Standards are designed to allow for extensions, including spreadsheets and additional types of content such as video. In addition to the content types defined in these Recommendations | International Standards, ODA also provides for arbitrary content types to be included in documents. These Recommendations | International Standards apply to the interchange of documents by means of data communications or the exchange of storage media. These Recommendations | International Standards provide for the interchange of documents for either or both of the following purposes: — to allow presentation as intended by the originator; — to allow processing, such as editing and reformatting. The composition of a document in interchange can take several forms: — formatted form, allowing presentation of the document; — processable form, allowing processing of the document; — formatted processable form, allowing both presentation and processing of the document. These Recommendations | International Standards also provide for the interchange of ODA information structures used for the processing of interchanged documents. This Recommendation | International Standard provides: — a mechanism for the identification of document fragments. Location expressions are used for this purpose; — the specification of external references; — the specification of subprofiles.