Make sure that any information resource (books, research reports, websites, newspaper articles, etc.) you use for an assignment passes the CRAAP test:
Currency: When was this information produced?
Relevance: Is the information important to your topic?
Authority: Who is the source?
Accuracy: How reliable is the information?
Purpose: Why was the information produced?
If you are unsure, look at this expanded list of questions to determine the value of your information resource.