code: public static boolean alg_33(int[] blz, int[] number) {
          int sum = addProducts(number, 4, 8, new int[]{6, 5, 4, 3, 2}, false);
          int crc = 11 - (sum % 11);
          if (crc > 9)
              crc = 0;
          return number[9] == crc;
      }
docs: TODO: hier weiter