  In this paper, we present a method of estimating referents of demonstrative
pronouns, personal pronouns, and zero pronouns in Japanese sentences using
examples, surface expressions, topics and foci. Unlike conventional work which
was semantic markers for semantic constraints, we used examples for semantic
constraints and showed in our experiments that examples are as useful as
semantic markers. We also propose many new methods for estimating referents of
pronouns. For example, we use the form ``X of Y'' for estimating referents of
demonstrative adjectives. In addition to our new methods, we used many
conventional methods. As a result, experiments using these methods obtained a
precision rate of 87% in estimating referents of demonstrative pronouns,
personal pronouns, and zero pronouns for training sentences, and obtained a
precision rate of 78% for test sentences.
