Because they appear at the end, citations might be the last thing a person thinks about when writing a paper. Most everyone has written a Bibliogrphy in one of its many fancy forms. But in reality the citations that form it are smattered across the paper, and glue the writer's idea together with facts, thought, and commentary from first and secondhand knowledge of outside experts, experiments, and experiences.
At worst, failing to cite your sources correctly will result in a charge of plagiarism that can ruin a paper or career. At best your readers will question your ability to prove your point without solid backing from reputable sources.
This guide will help you cite right, so your thoughts can speak for themselves.