@property<EOL><INDENT>def tissues_in_references(self):<DEDENT>
return [x[<NUM_LIT:0>] for x in self.session.query(models.TissueInReference.tissue).all()]<EOL>
Distinct tissues (``tissue`` in :class:`.models.TissueInReference`)

        :return: all distinct tissues in references
        :rtype: list[str]