In order to facilitate the international exchange of machine-readable bibliographic descriptions, the International Federation of Library Associations Working Group on Content Designators was organized in 1973 to arrive at a standard means of identifying data elements or providing additional information about a data element. In three meetings the group considered 52 working papers and arrived at 21 decisions, representing the majority viewpoint of the members. It was decided that the format would be designed to handle all media, including single-level and multi-level structures. Basic principles for assigning tags, indicators, and data element identifiers were also adopted. The 21 decisions are listed in concise form in Appendix B. (PF)