The authors describe and classify different hypertext documentation approaches by surveying a number of existing systems. They comprehensively list features of each system but do not numerically compare systems because of the subjective nature of evaluation. Instead, the data provided should be used as a basis for local comparisons by the reader. The classification breaks systems down according to publishing type, i.e. those designed for both publishing and accessing hypertext, either publishing or accessing documentation, and those that use general-purpose hypertext systems for document production and presentation. These categories are further subdivided according to functionality and specific system information.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>