Engineering & Physics

Primary sources are original sources created by a participant or observer of a historical event. Primary sources may include: letters, manuscripts, diaries, journals, newspapers, speeches, photographs, audio recordings, government documents, and videos. In the arts, primary sources also include original garments, sketches, wigs, etc.

Secondary sources are interpretations or analyses of an event, usually written by scholars after the event occurred.

Use Ulrich's Periodicals Directory to check if a journal is peer reviewed. If you see a referee shirt next to the title of the journal, it is peer reviewed.