For any source, you will need to evaluate it to determine whether or not it is reliable and relevant to your assignment. You can use the C.R.A.P. test--a mnemonic device--to help decide whether or not it's worth including in your resource list.
C = Currency
R = Reliability, Relevance
A = Authority, Audience
P = Purpose, Point of View
Each of the letters represents a key point for you to evaluate. Here are some more in-depth questions to ask about each source: