A contextual link is a reference together with content. Footnotes are a typical example. For this same reason, access to services is restricted. As a comparison, the rst users of databases could only make changes to data using procedures de ned by computer specialists. In this way computer specialists concentrate only on the functional layout of the data and the basic services.
End users can very easily develop their own processes to quickly meet their own speci c needs.
Information Technology Database languages SQL, third edition, November 1992. Finally, Section 6 gives an overview about related work and discusses future work. These element type definitions are specializations of the element type form. A contextual link is a reference together with content. Footnotes are a typical example.