The PCP results appeared in conferences in 1992, Sanjeev Arora's thesis appeared sometime after, and the "journal version" appeared in 1998. Similarly, the PRIMES in P result was announced in 2002, but was published in the Annals of Math in 2004.
If I'm trying to write something that talks about the history of a set of results (let's say I'm talking about PCP), it is generally recommended that I cite the definitive version (i.e the journal paper). So I'd talk about a PCP result "published in 1998", which seems silly given that everyone knows it appears much earlier. Given the lag time of CS journals, this is more of a problem than in other areas.
Is there any clean way out of this dilemma ? Should I cite the journal, but attempt to avoid any mention of dates in the text ? Should I use the "first published date" in the text, and cite both the earlier, conference version, AND the journal version ?
Maybe it doesn't matter, because the only results worth announcing well before publication are so famous that such questions are moot, and "everyone knows when it appeared". I don't have answers here: I'm just confused.