Deletion of Bucket (unit)

Comment: It takes little time to confirm that the equivalence of 1 bucket being 4 gallons was fairly well established in metrology - see ''https://books.google.co.uk/books?id=CrmuSiCFyikC&pg=PA46 The Science of Measurement: A Historical Survey'', for example.  There are obviously |alternatives to deletion such as merger with bucket which does not contain this fact and which we prefer per our |editing policy.  See also There's a Hole in My Bucket, which seems a good parody of these discussions
Stance: keep
Cited policy: Wikipedia:Deletion policy (WP:ATD||WP:PRESERVE)