⮚Media Type.
A change in the media type (337 field) of the serial is a major change requiring a new description..
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338 ## $a computer disc $b cd $2 rdacarrier
⮚Carrier Type.
A change in the carrier type (338 field) from online resource to another computer carrier and a change from another computer carrier to online resource are major changes and require a new description. All other changes in carrier type are minor. (CCM:16.4.1b)
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