I've substantially cut back and rewritten the article, removing a major section that was pure, unsourced WP:OR, and adding new information about earliest attestations from the 1950s sourced to a new, and apparently solid reference. This new source, however, is WP:TERTIARY, and thus should be replaced by proper WP:SECONDARY sources. Fortunately, this may not be as difficult as might otherwise be the case, since this tertiary source itself lists two secondary sources which should be tracked down and added to the article, replacing the current ref. The improved state of the article is such that the 2017 {{unreliable}} tag is no longer needed per WP:WTRMT, and so I removed it. Mathglot (talk) 08:52, 25 November 2019 (UTC)
It seems doubtful if this topic will ever gain enough content to be more than a stub, which would mean it fails WP:NOPAGE. Perhaps it should be considered for transwikification to Wikiquote? Mathglot (talk) 09:56, 25 November 2019 (UTC)