# Help:Editing/House Style/Citations

## Citations

It is good to indicate where the information comes from. This is done in $\mathsf{Pr} \infty \mathsf{fWiki}$ in the last of the page in a section called Sources.

There are several templates which can be used:

### Hardcopy Sources

Template:BookReference
This is used to reference a specific book which will have been documented in the ProofWiki:Books page. The idea of this is that if you have sourced the information for a page directly from a book, then it should be possible to provide the details of that book.

Example:

which can be found on the page Characteristic times Ring Element is Ring Zero.

Template:Citation
This is used to reference a specific article in a journal. This is still under development, as the individual Journal entries still need to be worked on.

Examples of their use can be found on various ProofWiki:Mathematicians pages, for example:

• 1908: Mathematical Logic as Based on the Theory of Types (Amer. J. Math. Vol. 30: 222 – 262)

which appears on the page for Bertrand Russell.

The style of this is still evolving.

### Online Sources

There are templates for the following online sources. Each one has been crafted so as to produce a reference in the style requested by the online source in question.

Template:MathWorld
This provides a direct link to a page on the http://mathworld.wolfram.com/ website.

Example:

which can be found in the page Area of Sector.

Template:Planetmath
This provides a direct link to a page on the http://planetmath.org/ website.

Example:

which can be found in the page Urysohn's Lemma.

Template:MacTutor Biography
This provides a direct link to a page on the http://www-history.mcs.st-andrews.ac.uk/history/index.html website.

Example:

which can be found in the page ProofWiki:Mathematicians/Hanna Neumann. Note that the link presentation is taken from the page the template is invoked from.

Example:

which can be found in the page Limit of Sine of X over X/Geometric Proof.

Template:Metamath
This provides a direct link to Metamath.

Example:

which can be found in the page Principle of Transfinite Recursion.

Template:OEIS
This provides a direct link to the On-Line Encyclopedia of Integer Sequences.

Example:

which can be found in the page Square Root of 2 is Irrational.

Template:TORI
This provides a direct link to the TORI source site.

Example:

which can be found in the page Definition:Tetration.

Template:SpringerOnline
This provides a direct link to a page on the Springer Online Encyclopedia of Mathematics.

Example:

which can be found in the page Definition:Ring (Abstract Algebra).

### Acceptability of Online Sources

NOTE: The above are the ONLY web resources which are to be used as general citation sources. Others may be added to the above as and when they come to our attention as being particularly useful. So feel free to challenge this assertion if you find something which appears to be a particularly rich and productive resource.

Scholarly papers which are available online may usually also be cited.

What are not generally acceptable include:

Lecture notes for university courses available online (because they do not stay online forever, and this causes dead links)
Links to pages in homework help forums
Discussion pages in any web forum
Wikipedia -- not because we don't like them, but because as they are self-proclaimed tertiary source, there is no need to do so -- we would rather go to the actual source works.