Separate fact from myth to avoid questions of integrity.
Paraphrasing does not relieve you of the responsibility to cite. Paraphrases and summaries require page references and bibliography entries, just like quotations do.
Study aids must be cited. Many students are reluctant to cite study aids (CliffsNotes, SparkNotes), online reference tools (Wikipedia), and other websites and blogs. But even resources you use just to spark your imagination or inspire you must be cited.
A web address is not adequate citation. A web address (e.g., www.adelphi.edu) is virtually never acceptable as a parenthetical in-text citation, nor will a web address alone suffice in a bibliography. See A Writer’s Reference for information on correctly citing web sites and other electronic resources within the various citation styles.
Quotations do not make your paper look better. Contrary to popular belief, overusing quotations suggests to your reader that you have not really understood what you have read, and that you have simply copied material to make it seem as if you have read carefully.
Introducing quotations does not break the flow. While some inexperienced writers fear that introducing sources will break the “flow” of their writing, the opposite is true: good writing clearly signals how the various sources of information fit together, while choppy writing jumps from source to source without signals.
When in doubt, cite. While common knowledge need not be referenced, there are gray areas. If you’re not sure whether to cite something, play it safe and cite it.