First,  there is no need for citations or bibliographic references in your responses. This is a test, not a research paper.
Second, you may optionally use outside materials or do additional research if you choose, but it is not expected or required.  Make sure that in your answer you draw sufficiently on the course readings to fully answer the question in terms of the arguments and evidence contained in the course readings.  Strengthening your answer by adding outside material is fine, but make sure you cover what the test questions require.