Help:Index/Formatting/References

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This help page is meant for help and guidance only. It can be edited by any Citizen and, whilst we try to ensure it is accurate, it may not fully represent current policy.

Further guidance can be found at the Citation style page.

See also CZ:List-defined references and CZ:Citation templates

(PD) Drawing: Milton Beychok
Example of a References section at bottom of an article.

This article is about formatting embedded inline references (also called notes or footnotes) in an article. They may provide sources where a reader can find discussion in more detail, or from a different background, or ramifications of the topic the article has not explored. Or, they may corroborate a specific word, statement, paragraph or even sub-section of an article by providing the readers of the article with the details of a book, journal, newspaper report or online website page that substantiates and validates the word, statement, paragraph or sub-section. The location of the word, statement, paragraph or subsection being referenced is marked with a superscript, bracketed number (colored blue) like this for a single reference^[1] or this^[2][3] for multiple references. All Citizendium article having a status of Developed or Approved should have a list of references in a "References" or "Footnotes" section at the end of the article.

In Citizendium and many other Wikis, the Wiki markup coding of embedded inline references on the edit page of an article always begins with the tag <ref> and ends with the tag </ref>. For that reason, the Wiki markup coding of embedded inline references is often referred to as the <ref> </ref> method.

In contrast to notes directed at specific content, some authors use the word "references" to mean listing the details of sources (such as books or journals) that provided information, corroboration or substantiation of the article as a whole rather than any specific parts of the article. Such lists are placed at the end of the article with no indication as to what specific part of the article each listed source applies. Within the context of Citizendium, in most cases, such non-specific references are best placed in the "Bibliography" subpage rather than at the end of the article. If such reference lists include hyperlinks to online website pages, then they are best included in the "External Links" subpage. In some few cases, an article may benefit by having a short list of about 3 books in a section entitled "Further reading" in addition to the "References" or "Footnotes" section and the "Bibliography" subpage.

Some authors also use embedded inline hyperlinks like this [http://webbook.nist.gov/cgi/cbook.cgi?Name=Isooctane&Units=SI&cTC=on#Thermo-Condensed] as references. Such references should not be used because they display a number in the text, like this [1], which will be confused with the numbered footnotes in the Reference section at the end of the article. If the url is followed by a space and a description, only the words will show in the text: Pentane: C₈H₁₈. The writer must decide whether to place such links on the External links subpage, whether to use an inline link as just described, or whether to use a true numbered footnote with the {{cite web...}} template found at CZ:Citation templates, a more appropriate choice where the link is meant to support a specific item in the text.

No rules or guidance about references are cast in stone and must absolutely be followed. However, following the methods and guidance in this article will result in consistency from one article to another and, for that reason, it is strongly recommended they be followed.

Valid, reliable references

A reference must be accurate, reliable and it must support the text. To elaborate upon, or to validate or corroborate the statement that "Mike Brown climbed Mount Everest", referencing a publication about Mount Everest is no good if Mike Brown isn't mentioned. Similarly, referencing an article about Mike Brown is also no good if it doesn't mention that he climbed Mount Everest. The referenced source must relate to Mike's achievement, and if corroboration is sought, say specifically what is to be verified.

We must use reliable, credible sources such as published books, professional journals, mainstream press report , and reliable web sites. Blogs, MySpace, YouTube, fan sites and extreme minority material are not usually acceptable, nor are your own unpublished essays or research. Wikipedia articles or other Citizendium articles are not reliable sources.

Inserting the embedded inline references

Single insertion of a reference:

For the single insertion of a reference, <ref>{{cite xxx |...}}</ref> is placed on the CZ article's edit page at the insertion point of the reference, where xxx is book, journal or web. This insertion will display a number in the text^[1] linked to the corresponding numbered footnote in the References section.

For example, insertion at a location in the text of:

<ref>  {{cite web|url=http://www.eia.doe.gov/bookshelf/brochures/gasoline/index.html |title=Where our gasoline comes from |date= April 2008 |publisher=U.S. Energy Information Administration |work=Energy Explained |accessdate=2011-05-14}}  </ref>

results in the footnote as follows:

1.↑ Where our gasoline comes from. Energy Explained. U.S. Energy Information Administration (April 2008). Retrieved on 2011-05-14.

The writer has flexibility in how much detail is provided to the template.

Insertion of the same reference more than once:

When the same reference is used several times, the reference tag <ref> is expanded to include a one-word name for the reference <ref name=xxxxx>, where xxxx is an arbitrary choice by the writer, but may not include punctuation other than underscores '_'. This one-word name insertion is placed on the CZ article's edit page at the first insertion point of the reference:

<ref name=Speight>

{{cite book|author=J. G. Speight|title=The Chemistry and Technology of Petroleum|edition=4th Edition|publisher=CRC Press |url=<nowiki>http://books.google.com/books?id=ymL2S9RWzx4C&printsec=frontcover |year=2006|id=ISBN 0-8493-9067-2}}

</ref>

where spaces are introduced just to make reading easier. At the second insertion point of the reference the insertion is made:

<ref name=Speight/>

And at the third insertion point of the reference:

<ref name=Speight/>

and so forth, for further insertion points. With these three inserts in a line of text, the result is:

Petroleum is important.[1] It is used in plastics,[1] and for fuel.[1]

..................................................................................................

1. ↑ 1.0 1.1 1.2 J. G. Speight (2006). The Chemistry and Technology of Petroleum, 4th Edition. CRC Press. ISBN 0-8493-9067-2.

The References section at the end of the CZ article is discussed next.

Producing the reference or footnote list:

On the edit page of the CZ article, place either of these at the bottom of an article to produce a references or footnotes section:

==References==	==Footnotes==
{{reflist}}	{{reflist}}

Either of the above formats produces a references or footnotes section at the bottom of the CZ article's main page containing a list such as just below, and note that the list numbers are automatically generated:

In some cases, when there are a large number of references and many of them are fairly short, space can be conserved by using {{reflist|2}}, instead of {{reflist}}, which splits the reference list into two columns.

Where to place the reference insertion points

The correct placement of the reference insertions is illustrated by a realistic example:

The crude oil distillation unit is the first processing unit in a petroleum crude oil refinery. It separates the crude oil into petroleum naphtha and other intermediate refinery products. Those intermediate products are subsequently further processed in other units so as to produce sales products such as gasoline, diesel oil, fuel oils and asphalt.

References

Note the placement of the references in the above example. These are the "rules":

• A reference for a sentence is inserted immediately after the period at the end of the sentence, with no space between the period and the reference.
• A reference for a single word (that is not followed by a comma) is inserted immediately after the word, with no space between the word and the reference.
• A reference for a single word (that is followed by a comma) is inserted immediately after the comma, with no space between the word and the comma.
• Two or more references at the same point of insertion are placed immediately next to each other with no space between the references.

How to use the links

• Clicking on the blue superscript ^1.0 causes the screen display to scroll back up to the point where the first reference to Speight's book was inserted. Clicking on the blue superscript ^1.1 causes the screen display to scroll back up to the point where the second reference to Speight's book was inserted. Clicking on the blue superscript ^1.2 causes the screen display to scroll back up to the point where the third reference to Speight's was inserted ... and so forth.

• Clicking on any up arrow (↑) in the reference list that has no associated superscripts causes the screen display to scroll back up to the point where that single-use references was inserted.

• Clicking on the superscript bracket reference numbers anywhere in the article's text cause the screen to scroll down far enough to display that reference in the reference list.

Try it out!

How to reference books, journals and the web

A number of templates are available to format the text between the <ref> and </ref> tags in a more structured way. Some of those templates are quite complicated and it is probably best for new authors to use simpler ones. Experienced authors may wish to explore the more complicated templates available at {{cite book}} or {{cite journal}},

The following examples do not cover every method of referencing books and articles. But they do provide enough information so that beginners can produce satisfactory references.

Referencing books

This is example template of a simple book reference that provides the needed essentials:

{{cite book|author=|title=|edition=|publisher=|year=|pages=|id=ISBN XXXX }}

and this is how it would appear on a CZ article's edit page:

{{cite book|author=John Smith|title=The Age of Reason|edition=2nd Edition|publisher=Johnson Press|year=2007|id=ISBN 0-5678-4325-1}}

which automatically produces this in the references list at the bottom of a CZ article's main page:

John Smith (2007). The Age of Reason, 2nd Edition. Johnson Press. ISBN 0-5678-4325-1.

if the edition is unknown, then simply leave it blank, thus on a CZ article's edit page:

{{cite book|author=John Smith|title=The Age of Reason|edition=|publisher=Johnson Press|year=2007|id=ISBN 0-5678-4325-1}}

Here is a somewhat more elaborate example in vertical format (the order does not matter; the template sorts the results):

<ref name=Halmos>{{cite book

|title=Naive set theory

|author=Paul Richard Halmos

|chapter=Section 9: Families

|url=http://books.google.com/books?id=x6cZBQ9qtgoC&pg=PA34

|pages=pp. 34 ff

|isbn= 9780387900926

|publisher=Springer

|year=1998

|edition=Reprint of 1960 ed }}</ref>

A single-line format works just as well. This insertion in the text of the article results in an entry at the {{Reflist}} location:

1. ↑ Paul Richard Halmos (1998). “Section 9: Families”, Naive set theory, Reprint of 1960 ed. Springer, pp. 34 ff. ISBN 9780387900926. 

In this example, a link to Google books is provided. This link is truncated at the page number, which makes the url shorter at the cost of eliminating the highlighting of the search terms in the retrieved page. Because the reference has been named, it can be referred to again somewhere else in the article using the insertion in the text <ref name=Halmos/> with a forward slash.

Referencing journals

A simple reference to a journal article that includes: the author's name, followed by the date in parenthesis and a period. That is followed by the article title in quotation marks also followed by a period. That is followed by the name of the journal in italic font and not followed by a period. Next is the journal's volume number in bold font, followed by the pages of the article in plain font (not bold and not italic). Below is an example of how the reference would appear on a CZ article's edit page:

<ref>W.B. Kay (1936). "Gases and Vapors At High Temperature and Pressure". ''Industrial Engineering & Chemistry'' '''28''': 334-336 </ref>

which produces this in the references list at the bottom of a CZ article's main page:

W.B. Kay (1936). "Gases and Vapors At High Temperature and Pressure". Industrial Engineering & Chemistry 28: 334-336

A preferable method is to use the {{cite journal...}} template found at CZ: Citation templates:

<ref>{{cite journal

|author=James A. Bierlein, Webster B. Kay

|title=Phase-Equilibrium Properties of System Carbon Dioxide-Hydrogen Sulfide

|journal=Ind. Eng. Chem.

|volume=vol 45

|issue= 3

|date=March, 1953

|pages=pp 618–624

|doi=10.1021/ie50519a043

|url=http://pubs.acs.org/doi/abs/10.1021/ie50519a043}}

</ref>

which may be strung out in a single line, if so desired. This entry produces a more complete entry using a standard format in the references list at the bottom of a CZ article's main page:

1. ↑ James A. Bierlein, Webster B. Kay (March, 1953). "Phase-Equilibrium Properties of System Carbon Dioxide-Hydrogen Sulfide". Ind. Eng. Chem. vol 45 (3): pp 618–624. DOI:10.1021/ie50519a043. Research Blogging.

Referencing online website pages

The simplest correct way to reference material from an online website page is to start with square bracket, followed by the url of the website page, followed by a single space, followed by a title for the material and ended with another square bracket. For example, enter this on the CZ article's edit page:

<ref>[http://www.eia.doe.gov/energyexplained/index.cfm?page=gasoline_where Where our gasoline comes from]</ref>

which produces this in the references list at the bottom of a CZ article's main page:

1. ↑ Where our gasoline comes from

It is preferable to use the {{cite web... }} template found at CZ: Citation templates, which prompts for relevant information about the source:

<ref>{{cite web

|url=http://www.eia.doe.gov/bookshelf/brochures/gasoline/index.html

|title=Gasoline explained: Where our gasoline comes from

|date= April 2008

|publisher=U.S. Energy Information Administration

|work=Energy Explained

|accessdate=2011-05-14}}

</ref>

which may be strung out on a single line, if one wishes. This insertion produces this in the references list at the bottom of a CZ article's main page:

1. ↑ Gasoline explained: Where our gasoline comes from. Energy Explained. U.S. Energy Information Administration (April 2008). Retrieved on 2011-05-14.

It is strongly recommended that, under no circumstances, should a references ever include a un-bracketed "bare" url . In other words, references on a CZ article's edit page should never be formatted like this:

<ref>http://www.eia.doe.gov/energyexplained/index.cfm?page=gasoline_where Where our gasoline comes from</ref>

which would produce this undesirable reference format in the references list at the bottom of a CZ article's main page:

1. ↑ http://www.eia.doe.gov/bookshelf/brochures/gasoline/index.html Where our gasoline comes from

Take the time to correctly format references to online website pages.

Summary

This article is based on "boiling down" the many other CZ "help", "how to" and "style" articles containing guidance on how to format and use references or citations (not all of which are inter-consistent) into one single, coherent article devoted completely to explaining how to format references. It is also based on a great deal of experience in formatting references for CZ and other Wiki articles.

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