Where can you find a list of credible sources on the internet, like website for research papers.
Critical reading is the best guide to content credibility. In the early days, sites with .edu were reliable, but I find that is no longer a reliable guide. My advice is to read. There is a lot of good info on the web, and some trash.
These sites have updated information and exercises you can use to help learn to tell the good from the awful:
http://lib.nmsu.edu/instruction/eval.html
http://www.sou.edu/library/searchtools/
Scroll down to the link for evaluating websites.
And, as Bobpursley has said, read, read, read!!
=)