https://en.wikipedia.org/wiki/Wikipedia:Verifiability#Access_to_sources https://en.wikipedia.org/wiki/Wikipedia:Verifiability#Access... specifically allows the

https://en.wikipedia.org/wiki/Wikipedia:Verifiability#Access_to_sources https://en.wikipedia.org/wiki/Wikipedia:Verifiability#Access... specifically allows the use of sources that are hard to access. The rule here wasn't that it couldn't be used because it was hard to access, but that it couldn't be used because it wasn't published at all. Furthermore, any sane editor would allow use of this information under Ignore All Rules (https://en.wikipedia.org/wiki/Wikipedia:Ignore_all_rules https://en.wikipedia.org/wiki/Wikipedia:Ignore_all_rules ), which is specifically there because sometimes the rules don't produce good results.