Why cite sources?
As an academic writer, you must document fully any borrowed ideas and words. The academic citation--author, page number, and bibliographic entry--establishes two things beyond your reliability and credibility:
When you provide an academic citation, you've made it clear who and what you've read, how you've used the source in your paper, and where others can find it.
From: Lester, James D. and James Lester, Jr. Writing Research Papers. New York : Pearson Education, 2005, p. 92 (REF LB 2369 .L4 2005)