NEPHIS is an elegant and parsimonious system for storing document-descriptor relationships and generating a printed index for a bibliography or similar reference work, or for arranging online search output for ease of browsing. The system runs on a PET microcomputer.

This article describes how thesaural (descriptor-descriptor) relationships can be represented using the basic NEPHIS formalism with slight extensions. In a NEPHIS database augmented by thesaural relations, one can search inclusively (a search for computers retrieves also references on microcomputers).

The article, which is not always easy reading, details the algorithms used. To understand this article, the reader must know NEPHIS as described in previous work cited in the bibliography.