amazon standard identification number barcode bhutan book coden check digit checksum china chinese language code commerce currency denmark eas ebs england english language european article number french language german language germany global trade item number hyphen identifier information technology international organization for standardization international standard audiovisual number international standard music number international standard musical work code international standard recording code international standard serial number japanese language library library of congress library of congress control number magazine modular arithmetic north america online computer library center portable document format prefix prefix code prime number russian language serial item and contribution identifier sweden the ultimate alphabet urn united states universal product code