When you write a research paper or report you need to include a bibliography or a list of the books, articles, or other publications that you used in your research.The pieces of information used to describe a specific publication are grouped together to make up a citation or a bibliographic citation.
Why you need to cite your sources:
Let your readers know that what you write is based on established research, that you didn't just make it up.
Help readers who want to retrace your steps or recreate your work.
Demonstrate your knowledge of the field and your familiarity with the professional literature.