Microsoft Applications: “[...] and 0.5 defect per KLOC [...] in released product (Moore 1992).”
Edit: Also, I somehow have the feeling that the quote about defects per KLOC isn't really helping.
From what I see regularly, the business side of things is almost never interested in the "0 defects per .5 MLOC" of the last part, especially if you're considering what the implications must be for the amount of time it takes to produce that level of quality (even more so if you assume some form of waterfall development, as it's attributed to 1990).
I really like what the author is saying after that (because he focuses on much more important factors) but that only makes this specific quote seem more misplaced to me.