When an eBook is uploaded onto RedShelf.com, it is often the source file that's typically used by the publisher to print the physical book. This means any media, Publisher Product/Access Codes, CDs, Lab Manuals, etc that might have come bundled with the physical book are unable to be appended to the digital version for formatting and copyright reasons.
Don't worry though! Some supplemental material can be found for free on the publisher's website. Our team has tracked down everything from Spotify playlists, Internet Archive articles assigned by professors, websites that haven't been updated since the 90's -- so if you're having trouble locating a particular resource: let us help!