Unfortunately, there is no universally agreed-upon "style" for documenting the use of sources in research -- no single method for formatting footnotes, bibliographies, endnotes, in-text citations, etc. Instead, there are more than a half-dozen, most of which are specialized for use in one or more subject areas.
The W&L University Library maintain a collection of resources on these styles:
Plagiarism is described in the W&L 2014-2015 Catalog, and cited by the Student Executive Committee, as "the use of another's words or ideas without proper ackowledgement."
The resources below should be considered reliable sources of advice about what constitutes plagiarism and how to avoid it.
Of these, the W&L Student EC's Plagiarism Pamphlet is the most "local," but the specially-selected guides from other institutions are more detailed.