The above dedinition remains among the most comprehensive by including services,
architecture, content, enabling technologies, users and content. It provided a basis for further discussion and refinement. The Digital Library Initiative, announced in September, 1993 (and since dubbed `DLI-1'), defined the term only implicitly (National Science Foundation, 1993),stating that ``Information sources accessed via the Internet are the ingredients of a digital library''.
Further, ``the problem for research and development is... to achieve an economically