Most journal articles are secondary sources. They are written by experts/scholars and interpret data/research findings. They can be described as at least one step removed from the event or phenomenon under review. Secondary source materials interpret, assign value to, conjecture upon, and draw conclusions about the events reported in primary sources.
Secondary sources are usually in the form of published works such as journal articles or books, but may include radio or television documentaries, or conference proceedings.
Here is a list of scholarly research databases where you can locate secondary sources for your interpretive essays.
Also useful:
Remember, secondary information is being viewed and interpreted through the eyes of the writer/interpreter. This must be taken into account when one is attempting to critically assess the value of the source material.
The following questions might be asked to help ascertain the nature and value of secondary material: