Deletion of 'The Night Mail'

Comment: as non-notable poem that is relevant to the film it was written for. No particular information needs to be preserved since the article already gives some mentions of it. All sources I can find are blogs or lyrics sites, or they only give a short mention of the poem. (If they copy-paste the poem but don't elaborate on it beyond a single sentence, it still fails 
Stance: merge
Cited policy: Wikipedia:Notability (WP:SIGCOV)