select distinct paper from paper_master,printsize_master,np_master,stamps where stamps.paper_code=paper_master.paper_code and paper_master.paper<>' '  and printsize_master.printsize_code=stamps.printsize_code and printsize_master.printsize=\'2.56 x 2.5\'  and year(stamps.issue_date)=1969  and stamps.serial_no=\'0594\'  and np_master.np_code=stamps.np_code and np_master.np=\'P\'  order by paper