When tasked with updating someone else's research document, consider the essence of the document’s work cited sources. You may have to do a bit of background sleuthing to answer questions about sources unfamiliar to you.
Who sponsored the research of the source?
Who was the intended audience of the source?
When was the source's information collected or published?
Where was the source published?
Book? Newspaper article? Government publication? etc.
Why did the author include this source as supporting evidence for his/her research?
Statistics to provide background? Emotional appeal? Research evidence to prove a point? etc.
Understanding the sources the author used to support his/her argument will help guide your research for more current information. You may question the credibility or relevancy of some of the author's sources. You may see opportunities to use similar types of sources or look at perspectives from sources the author overlooked. Using the original works cited page as a guide, you can fill in gaps or go in different directions.
After reviewing a source ask yourself:
How does this source help me as I research for my own paper?
All examples taken from Gregory Mantsios' "Rewards and Opportunities: The Politics and Economics of Class in the U.S." in Rereading America: Cultural Contexts for Critical Thinking and Writing, ed. Gary Colombo et al. (Boston: Bedford Books, 1995).