The Adam Back as Satoshi case

I saw on an old reddit that someone said HashCash was talked about in 1997 on some mailing lists, including proof-of-work discussion and format. Can anyone point to the mailing list entries where Back described his exact proof of work, which might match or allude to his later 2002 HashCash paper? Would love to read the early musings of HashCash as of 1997 "version 0", if possible, but don't know where to find the legit source material. tanks!