Where there are credits at the release level (front cover, back cover, spine, medium as major sources, obi and booklet as slightly more secondary), those apply at the release level in MB too. Even for releases with just one track.
If there are no credits for the release separately, you could use the track credits.
If credits are inconsistent (front says X, spine says Y, obi says Z), it can become more of a judgment call.
In this case, it seems fairly straightforward.