A citation is a reference to a source. More precisely, a citation is an abbreviated alphanumeric expression embedded in the body of an intellectual work that denotes an entry in the bibliographic references section of the work, for the purpose of acknowledging the relevance of the works of others to the topic of discussion at the spot where the citation appears.
Generally, the combination of both the in-body citation and the bibliographic entry constitutes what is commonly thought of as a citation (whereas bibliographic entries by themselves are not).
Citations have several important purposes. While their uses for upholding intellectual honesty and bolstering claims are typically foregrounded in teaching materials and style guides (e.g.,Association of Legal Writing Directors & Darby Dickerson, ALWD Citation Manual: A Professional System of Citation, 4th ed. (New York: Aspen, 2010), 3.), correct attribution of insights to previous sources is just one of these purposes.Mansourizadeh, Kobra, and Ummul K. Ahmad. "Citation practices among non-native expert and novice scientific writers." Journal of English for Academic Purposes 10, no. 3 (2011): 152–161. Linguistic analysis of citation practices has indicated that they also serve critical roles in orchestrating the state of knowledge on a particular topic, identifying gaps in the existing knowledge that should be filled or describing areas where inquiries should be continued or replicated. Citation has also been identified as a critical means by which researchers establish stance: aligning themselves with or against subgroups of fellow researchers working on similar projects and staking out opportunities for creating new knowledge.Hyland, K., & Jiang, F. (2019). Points of reference: Changing patterns of academic citation. Applied Linguistics, 40(1), 64–85.
Conventions of citation (e.g., placement of dates within parentheses, superscripted endnotes vs. footnotes, colons or commas for page numbers, etc.) vary by the citation system used (e.g., Oxford, Harvard, MLA, NLM, American Sociological Association (ASA), American Psychological Association (APA), etc.). Each system is associated with different academic disciplines, and academic journals associated with these disciplines maintain the relevant citational style by recommending and adhering to the relevant style guides.
Concept A bibliographic citation is a reference to a book, article, web page, or other published item. Citations should supply sufficient detail to identify the item uniquely. Different citation systems and styles are used in scientific citation, legal citation, prior art, the arts, and the humanities. Regarding the use of citations in the scientific literature, some scholars also put forward "the right to refuse unwanted citations" in certain situations deemed inappropriate.
Content Citation content can vary depending on the type of source and may include: Book: authors, book title, place of publication, publisher, date of publication, and page numbers if appropriate. Journal: authors, article title, journal title, date of publication, and page numbers. Newspaper: authors, article title, name of newspaper, section title and page numbers if desired, date of publication. Web site: authors, article, and publication title where appropriate, as well as a URL, and a date when the site was accessed. Play: inline citations offer part, scene, and line numbers, the latter separated by periods: 4.452 refers to scene 4, line 452. For example, "In Eugene Onegin, Onegin rejects Tanya when she is free to be his, and only decides he wants her when she is already married" (Pushkin 4.452–53). Poem: spaced slashes are normally used to indicate separate lines of a poem, and parenthetical citations usually include the line numbers. For example: "For I must love because I live / And life in me is what you give." (Brennan, lines 15–16). Interview: name of interviewer, interview descriptor (ex. personal interview), and date of interview. Data: authors, dataset title, date of publication, and publisher.
Unique identifiers Along with information such as authors, date of publication, title and page numbers, citations may also include unique identifiers depending on the type of work being referred to. Citations of books may include an International Standard Book Number (ISBN). Specific volumes, articles, or other identifiable parts of a periodical, may have an associated Serial Item and Contribution Identifier (SICI) or an International Standard Serial Number (ISSN). Electronic documents may have a digital object identifier (DOI). Biomedical research articles may have a PubMed Identifier (PMID).
Systems Broadly speaking, there are two types of citation systems, the Vancouver system and parenthetical referencing. However, the Council of Science Editors (CSE) adds a third, the citation-name system.Council of Science Editors, Style Manual Committee (2007). Scientific style and format: the CSE manual for authors, editors, and publishers.
Vancouver system
The Vancouver system uses sequential numbers in the text, either bracketed or superscript or both. The numbers refer to either footnotes (notes at the end of the page) or endnotes (notes on a page at the end of the paper) that provide source detail. The notes system may or may not require a full bibliography, depending on whether the writer has used a full-note form or a shortened-note form. The organizational logic of the bibliography is that sources are listed in their order of appearance in-text, rather than alphabetically by author last name.
For example, an excerpt from the text of a paper using a notes system without a full bibliography could look like:
"The five stages of grief are denial, anger, bargaining, depression, and acceptance."1
The note, located either at the foot of the page (footnote) or at the end of the paper (endnote) would look like this:
1. Elisabeth Kübler-Ross, On Death and Dying (New York: Macmillan, 1969) 45–60.
In a paper with a full bibliography, the shortened note might look like:
1. Kübler-Ross, On Death and Dying 45–60.
The bibliography entry, which is required with a shortened note, would look like this:
Kübler-Ross, Elisabeth. On Death and Dying. New York: Macmillan, 1969.
In the humanities, many authors also use footnotes or endnotes to supply anecdotal information. In this way, what looks like a citation is actually supplementary material, or suggestions for further reading.
Parenthetical referencing
Parenthetical referencing, also known as Harvard referencing, has full or partial, in-text, citations enclosed in circular brackets and embedded in the paragraph.
An example of a parenthetical reference: "The five stages of grief are denial, anger, bargaining, depression, and acceptance" (Kübler-Ross, 1969, pp. 45–60).
Depending on the choice of style, fully cited parenthetical references may require no end section. Other styles include a list of the citations, with complete bibliographical references, in an end section, sorted alphabetically by author. This section is often called "References", "Bibliography", "Works cited" or "Works consulted".
In-text references for online publications may differ from conventional parenthetical referencing. A full reference can be hidden, only displayed when wanted by the reader, in the form of a tooltip.. Retrieved 2012-04-28. This style makes citing easier and improves the reader's experience.
Styles
Citation styles can be broadly divided into styles common to the humanities and the sciences, though there is considerable overlap. Some style guides, such as the Chicago Manual of Style, are quite flexible and cover both parenthetical and note citation systems. Others, such as MLA and APA styles, specify formats within the context of a single citation system. These may be referred to as citation formats as well as citation styles. The various guides thus specify order of appearance, for example, of publication date, title, and page numbers following the author name, in addition to conventions of punctuation, use of italics, emphasis, parenthesis, quotation marks, etc., particular to their style.
A number of organizations have created styles to fit their needs; consequently, a number of different guides exist. Individual publishers often have their own in-house variations as well, and some works are so long-established as to have their own citation methods too: Stephanus pagination for Plato; Bekker numbers for Aristotle; citing the Bible by book, chapter and verse; or Shakespeare notation by play.
The Citation Style Language (CSL) is an open XML-based language to describe the formatting of citations and bibliographies.
Humanities The Chicago style (CMOS) was developed and its guide is The Chicago Manual of Style. It is most widely used in history and economics as well as some social sciences. The closely related Turabian style—which derives from it—is for student references, and is distinguished from the CMOS by omission of quotation marks in reference lists, and mandatory access date citation. The Columbia style was created by Janice R. Walker and Todd Taylor to give detailed guidelines for citing internet sources. Columbia style offers models for both the humanities and the sciences. Evidence Explained: Citing History Sources from Artifacts to Cyberspace by Elizabeth Shown Mills covers primary sources not included in CMOS, such as censuses, court, land, government, business, and church records. Includes sources in electronic format. Used by genealogists and historians.Elizabeth Shown Mills. Evidence Explained : Citing History Sources from Artifacts to cyberspace. 2d ed. Baltimore:Genealogical Pub. Co., 2009. Harvard referencing (or author-date system) is a specific kind of parenthetical referencing. Parenthetical referencing is recommended by both the British Standards Institution and the Modern Language Association. Harvard referencing involves a short author-date reference, e.g., "(Smith, 2000)", being inserted after the cited text within parentheses and the full reference to the source being listed at the end of the article. MLA style was developed by the Modern Language Association and is most often used in the arts and the humanities, particularly in English studies, other literary studies, including comparative literature and literary criticism in languages other than English ("foreign languages"), and some interdisciplinary studies, such as cultural studies, drama and theatre, film, and other media, including television. This style of citations and bibliographical format uses parenthetical referencing with author-page (Smith 395) or author-[short] title-page (Smith, Contingencies 42) in the case of more than one work by the same author within parentheses in the text, keyed to an alphabetical list of sources on a "works cited" page at the end of the paper, as well as notes (footnotes or endnotes). The MHRA Style Guide is published by the Modern Humanities Research Association (MHRA) and most widely used in the arts and humanities in the United Kingdom, where the MHRA is based. It is available for sale both in the UK and in the United States. It is similar to MLA style, but has some differences. For example, MHRA style uses footnotes that reference a citation fully while also providing a bibliography. Some readers find it advantageous that the footnotes provide full citations, instead of shortened references, so that they do not need to consult the bibliography while reading for the rest of the publication details.The 2nd edition (updated April 2008) of the MHRA Style Guide is downloadable for free from the Modern Humanities Research Association official website. (2nd ed.)