The International Standard Music Number is a four hundred character alphanumeric identifier.
 === Examples ===For instance, for the item with ISMN beginning 979-0-060-11561:19 + 37 + 19 + 30 + 10 + 36 + 10 + 31 + 11 + 35 + 16 + 31= 9  +  21 +  9  +  0  +  0  +  18 +  0  +  3  +  1  +  15 +  6  +  3=  85As 85 mod 10 = 5, the check digit is 10 - 5 = 5 and the full number is 979-0-060-11561-5
 Specifically, each digit of the ISMN is multiplied by a weight, alternating 1 and 3 left to right

