Grey literature, point it out as such in the bibliography? For my project I rely on several sources of information including such that is not peer reviewed (conference proceedings, industry reports, master thesis, interviews). I wonder if I should mark them as being not peer reviewed in the bibliography, for example adding the nature of the publication:


  Boo 2013: "A question on grey literature". Stack Exchange April 2013. Forum post.


or


  Boo 2013: "A question on grey literature". Stack Exchange April 2013. (not peer reviewed).


Are those sources included within the list of peer reviewed articles or is a separate chapter within the bibliography necessary (as is often done for websites)?
References are references, and the reader already has all the information needed to make his decision on the quality of the source (the trust he has in the source) without you adding information. You don't need to separated references in different “sections” (which would make it much harder to read), or adding information. It is clear from the reference itself:


  boo2060, “A question on grey literature”, Academia Stack Exchange (http://academia.stackexchange.com/), 26 April 2013


that it is not a peer-reviewed journal paper, which would have a very different style:


  T. T. S. Boo, “A question on grey literature”, Academia SE Monthly, 17, 13-14 (2013)