the citations of the paper is incomplete also, in that it does not mention finney's RPOW from 2004: http://www.finney.org/~hal/rpow/
quoting from there: "Security researcher Nick Szabo has coined the term bit gold for information objects which are provably costly to create"
bitgold as it was publicly described in 2005 was different than bitcoin in that there was a market for the tokens. bitcoin uses an agreement mechanism to establish the difficulty.
It's the worst date faking attempt in history if that was his intention - I think he republished his 2005 story after bitcoin to point out that he came up with these ideas.
quoting from there: "Security researcher Nick Szabo has coined the term bit gold for information objects which are provably costly to create"
bitgold as it was publicly described in 2005 was different than bitcoin in that there was a market for the tokens. bitcoin uses an agreement mechanism to establish the difficulty.