Soergel, D. (1985). Organizing Information. San Diego, CA: Academic Press. (Ch. 14: Index Language Structure)

This session will concentrate on conceptual structure, particularly hierarchy and facet analysis, as vehicles for index language construction, indexing, and ultimately information retrieval.

Semantic factoring leads to elemental descriptors, which might be useful in "post-combination". These elemental descriptors, in turn, may suggest facets of meaning that suggest a conceptual structure that can aid indexers and searchers in understanding how to find, assign, or select descriptors.

One of the important features of Soergel's approach to hierarchy is that it allows "polyhierarchy."

Soergel constructs a graphical representation of polyhierarchy.