  A system is described that uses a mixed-level knowledge representation based
on standard Horn Clause Logic to represent (part of) the meaning of natural
language documents. A variable-depth search strategy is outlined that
distinguishes between the different levels of abstraction in the knowledge
representation to locate specific passages in the documents. A detailed
description of the linguistic aspects of the system is given. Mixed-level
representations as well as variable-depth search strategies are applicable in
fields outside that of NLP.
