Common accepted online resources
Are there certain rescources that are discouraged from being used on this site? Is Wikipedia/-tionary not valid? Are there certain dictionaries or text books that are prefered over others?
I ask because I don't want to find the perfect answer to a question only to see that it's from Wiktionary and then have every one not consider the answer valid, etc.
(also I tried to search as best I could for a similar question, so sorry if it's a duplicate)