Answer:
Years in which the sources were published.
Step-by-step explanation:
In any citation of works in the literary world, the years are an important part of the validation process. It enables the reader to have a clear perspective and knowledge of where the works that have been cited are from. The inclusion of the years provides the valid proof of the book that has been used. Thus, the years mentioned in the works cited list are the years when the books or sources used were published.