When you quote or paraphrase text, cite facts, figures, or other data, or borrow ideas you find in work done by others, it is crucial to document your sources, both to avoid academic integrity violations and to ensure that your readers have the information they need to check your evidence or replicate your research.  For the sake of clarity and consistency, we usually do that using one of the formats listed below, which vary to suit various kinds of papers.  Each is linked to a site that can help you cite sources correctly and professionally.

 MLA (Modern Language Association) 

Commonly used for textually-based interpretive work, with in-text citations that identify a page number so that your reader can locate quoted material quickly and evaluate your interpretive argument.

Such buildings were first constructed in 1834 (Atkinson 34).

Chicago Manual of Style (Full Guide)

There are two types of Chicago Style: “Notes & Bibliography” and “Author-Date”.   The quick guides below are easier to use than the full guide and likely to provide sufficient information for most papers. 

Chicago Notes & Bibliography Quick Guide

Commonly used for research papers in the humanities that rely heavily on secondary sources.  Relegating citations to footnotes or endnotes prevents in-text citations from becoming obtrusive. 

Such buildings were first constructed in 1834.1

Chicago Author-Date Quick Guide

Commonly used for research in the natural or social sciences in which it helps a reader to know how recent a study was, and in which page numbers are less important because the findings of the study are generally agreed upon.  

Such buildings were first constructed in 1834 (Atkinson 2010).

APA (American Psychological Association)

The standard for research papers in psychology, for reasons similar to Chicago Author-Date style.

Such buildings were first constructed in 1834 (Atkinson 2010).

Anthropology (American Anthropological Association)

A hybrid system in which in-text citations includes both year of publication and page number. 

Such buildings were first constructed to 1834 (Atkinson 2010: 34).

The Purdue OWL (Online Writing Lab) is also a helpful source for MLA, Chicago, and APA style and general academic writing advice.  You may find their sample papers helpful:  MLA sample paper, Chicago Author-Date sample paper, Chicago Notes & Bibliography sample paper, APA sample paper.  Sometimes it is easier to emulate correct work than to follow a series of citation rules.