I'm confused regarding Hashcash, as Satoshi mention in white paper with date reference to 2002. But some sources suggest Adam Back published it in 1997[/li][/list]
that is because the paper was written 5 years after hashcash was released. see first sentence of abstract or citation [1] in the paper "Hashcash
was originally proposed as a mechanism to throttle systematic abuse of un-metered internet resources such as email, and anonymous remailers in May 1997"
[1]
http://hashcash.org/papers/announce.txt