Citation style

Citation style used at Citizendium is discussed specifically at Help:citation style

Scholarly and technical publications use many different formats for citing previously published work in their articles.

A citation allows the reader to verify a statement made in the text, to see the source of data, to gain more statistical detail, or to explore the original context of a quoted passage. Often, the text is marked with a superscripted number just after the section to which the citation is most relevant, or at the end of the relevant paragraph, where there may be more that one source indicated.

The superscripted mark may be a numeral, a Roman numeral, or a letter. Alternatively, the main authors of the cited reference source plus a date, in parentheses as in (Smith, 1997) may be provided. Variants of this approach are (Jones, 1997a) if Jones is cited for more than one 1997 article, and (Smith and Jones, 2000), and Timorof et al. 1927). Et al. is for et alia, meaning 'and others' in Latin, and this is usually used if there are more than three authors.

With word processing programs, it is easy to develop automatically generated, correctly numbered citations in documents. With Mediawiki software used for Citizendium, for example, there are good tools for annotating text with citations and generating a master list of sources, usually near the end of the article as end-notes. In some publications, citations are included in the footnotes on each page. Precise attention to the format and consistency of citations and other bibliographic information is expected in professional quality manuscripts.

Examples of citation styles

Here are three examples of citations from Proceedings of the National Academy of Sciences, USA, a well respected scientific journal (often called just PNAS by scientists).

1. Lockhart, P. J., Steel, M. A., Hendy, M. D. & Penny, D. (1994) Mol. Biol. Evol. 11, 605-612

2. Syvanen, M. & Kado, C. I., eds. (1998) Horizontal Gene Transfer (Chapman & Hall, London).

3. Day, M. (1998) in Horizontal Gene Transfer, eds. Syvanen, M. & Kado, C. I. (Chapman & Hall, London), pp. 144-167.

Citation 1 is a journal citation but unfortunately for the reader PNAS USA does not give the article's title. Note the volume number is given in bold text, followed by page numbers. 2 is a book and 3 a book chapter.

The following another PNAS USA citation of an article in the journal Molecular Biology and Evolution, published by Oxford Journals:

4. Lake, J. A. (1991) Mol. Biol. Evol. 8, 378-385

It is available on line as a pdf file

Here we will find, at last, an article title:

Letter to the Editor. The Order of Sequence Alignment Can Bias the Selection of Tree Topology. James A. Lake

In the text of Lake (1991), the citation style is like this: (Lake et al. 1984; Woese and Olsen 1986), and in the end-notes the citations are listed like this:

LITERATURE CITED

BALDACCI, B., F. GUINET, J. TILLIT, G. ZACCAI, and A.-M. DE RECONDO. 1990. Functional

implications related to the gene structure of the elongation factor EF-Tu form Halobacterium

marismortui. Nucleic Acids Res. 18:507-511.

The article titles are given in full, but the system for providing page numbers is different from PNAS USA, and the author's names are capitalized.

In short, many different citation styles are used today in scholarly literature.

How can authors work out how to cite publications correctly

A guide for how to provide citation details is provided to prospective authors by each scholarly publication. One accessible example is from the internet publication Public Library of Science Biology (PLoS Biology), an Open Access journal. They give the following guidelines for submitted manuscripts:

"PLoS uses the numbered citation (citation-sequence) method. References are listed and numbered in the order that they appear in the text. In the text, citations should be indicated by the reference number in brackets. Multiple citations within a single set of brackets should be separated by commas. Where there are more than three sequential citations, they should be given as a range. ... For all references, list the first five authors; add "et al." if there are additional authors. You can include a DOI number for the full-text article as an alternative to or in addition to traditional volume and page numbers. Please use the following style for the reference list:

Published Papers

1. Sanger F, Nicklen S, Coulson AR (1977) DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A 74: 5463–5467.

Accepted Papers

Same as above, but "In press" appears instead of the page numbers. Example: Adv Clin Path. In press.

Electronic Journal Articles

1. Loker WM (1996) "Campesinos" and the crisis of modernization in Latin America. Jour Pol Ecol 3. Available: http://www.library.arizona.edu/ej/jpe/volume_3/ascii-lokeriso.txt. Accessed 11 August 2006.

Books

1. Bates B (1992) Bargaining for life: A social history of tuberculosis. Philadelphia: University of Pennsylvania Press. 435 p.

Book Chapters

1. Hansen B (1991) New York City epidemics and history for the public. In: Harden VA, Risse GB, editors. AIDS and the historian. Bethesda: National Institutes of Health. pp. 21–28."

(End of direct quote from PLoS Biology)

Practice at Citizendium

The principles behind the choice of any style of citations to provide the reader with enough information to find the source for himself or herself, with efficient use of limited space and an aesthetically pleasing appearance on the page. Although Citizendium is an electronic encyclopedia, there are nevertheless limitations on space to enable articles to be printed compactly. Electronic links mean that, strictly, fewer details need be given to enable sources to be located efficiently - for a citation on PubMed everything is redundant except the PMID number. However citations do more than merely point to a source, they are also open acknowledgements of the origin of ideas and information. Listing sources clearly is an explicit and courteous recognition of the debt that authors have to other authors.