Record a standard identifier as it appears on the resource. Some systems may require omission of internal punctuation.
Examples:
Dublin Core (elements)
0-7849-2784-7
008888333036
333036
ULUS 10070
MODS
0784927847
008888333036
333036
ULUS 10070
MARC/RDA
020 0784927847
024 1 008888333036
028 52 333036 $b Ubisoft
024 8 ULUS 10070