Specifies a data structure known as the SGML Document Interchange Form (SDIF). SDIF enables a document conforming to AS 3514-1987 (ISO 8879:1986) which might be stored in several entities, to be packed into a data stream for interchange in a manner that will permit the recipient to reconstitute the separate entities. SDIF also allows related documents to be included in the data stream, such as covering letters, transmittal forms, catalogue cards, formatting procedures, or the 'document profile' required by a document architecture. This Standard is technically identical with and reproduced from ISO 9069:1988.