All scholarly/peer review articles contain an abstract.
Definition: an abstract is a summary of the research article, often written by the author(s).
What does this mean for you?
Search strategy: look at the abstracts in the database [e.g., LionSearch, Sociological Abstracts, Criminal Justice Abstracts] before going to the full text of the article.
What about books?
Book reviews can be used the same way as abstracts. Note: this is not required for this specific assignment, but can be useful to know about in your professional and academic career.
Definition: book reviews are often journal articles written by authors who did not write the book and who can provide both critical and positive analysis. Reading more then one is important for gaining perspective.