If the information in a paper or project does not come from you, the writer, then it comes from another source. Documenting, citing, and referencing your sources makes it clear to others where the information you used came from and gives credit to those sources.
Primary sources provide first-hand testimony or direct evidence concerning a topic. Primary sources include documents, sound and video recordings, and other types of information that were created at or near the time being studied. Abraham Lincoln’s 1863 speech “The Gettysburg Address” is an example of a primary source.
Secondary sources provide second-hand information or indirect evidence concerning a topic. Secondary sources provide information based on research about or interpretation of a primary source. Lincoln, David Herbert Donald’s 1996 biography of Abraham Lincoln, is an example of a secondary source.