UPC: GTIN-12, the 12-digit number including check-digit. If less than 12-digits, such as UPC-E which is 8-digits, add leading zeros up to 12-digits.;
GTIN: GTIN-14, the 14-digit number including check-digit. If less than 14-digits add leading zeros up to 14-digits.
ISBN: International Standard Book Number, the 10 or 13-digit number including check-digit.;
EAN: GTIN-13, the 13-digit number including check-digit. If less than 13-digits add leading zeros up to 13-digits.
