This paper reports on a study of pronouns this, that, and it in articles in the New York Times, testing the following hypotheses: (1) the pronoun it requires its referent to be in the addressee’s focus of attention; demonstrative pronouns only require activation; (2) the anaphoric relation between it and its antecedent tends to be direct (co-referential); the relation between a demonstrative pronoun and its antecedent tends to be indirect (non-coreferential).
Gundel, Jeanette, Nancy Hedberg, and Ron Zacharski. 2007. Directly and Indirectly Anaphoric Demonstrative and Personal Pronouns in Newspaper Articles. Proceedings of the Sixth Annual Discourse Anaphora and Anaphora Resolution Colloquium (PDF)