Each record will list subjects that the item is about. With these books or pamphlets from the library Sam should get a good historical perspective on his topic and probably some statistics. Current information is most often found in periodicals, or things that are published frequently and regularly. Sam's assignment specifies that the material must be scholarly. In general, scholarly publications will be journals, not magazines.
Magazines contain more popular material.
As a rule, journals use formal, technical language or terminology. They report on research findings or describe research methodologies. They also cite other scholarly material to support the position they present. Magazine articles on the other hand are written for the general population. The articles tend to be short, the author's name may or may not be listed, and the author may or may not cite other works.