So I know this borders on self-promotion (what me – never), but there is an excellent article on credibility and newspapers on the Columbia Journalism Review site at:
http://www.cjr.org/the_news_frontier/trust_falls.php?page=all
I found it because it quotes from my Journal of Documentation piece, but other than that it is a good. Seriously it does a great job of making real some of the points I raise in that article. I think it has a lot of food for thought (the Columbia piece) in terms of librarians acting as authorities versus authoritarians, giving it a reality I could never muster.