This answer applies here as well.
According to the optimization guide, in section 2.4.4 dealing with Nehalem generation caches:
The L1 and L2 caches are writeback and non-inclusive.
The shared L3 cache is writeback and inclusive
This must be a typo in the 2nd article, note that in the text itself the inclusiveness is only mentioned regarding the L3, they must have copy pasted it in the summary below.
There is also not much sense in making 2 levels inclusive, the L3 already serves to filter snoops.