The discussion that follows in this thesis analyzes the question of back-reference to a singular and plural [-HUMAN] noun phrase with a [+HUMAN] pronoun being in focus position. According to previous literature, a weak pronoun cannot refer to an inanimate noun phrase in a focus position as they are not suitable for a stressed position. The thesis provides the results of an online survey, which takes a look at the grammaticality judgments for sentences with singular and plural antecedents bearing the [-HUMAN] feature in the input clause, and with co-referring pronouns in focus position in the output clause. The pronouns appear in four grammatical cases: ablative, accusative, dative, and superessive.