\bibitem is a command used to enter a reference in a thebibliography environment in your document. The syntax for using \bibitem is \bibitem[label]{key}.

The optional [label] is for you to add your own labelling system for the bibliography entry. If no label is set, the entries will be set in numerical order: [1], [2], [3], etc.

The argument {key} is used to reference and link the commands \bibitem and \cite to each other and the information they contain. The command \cite contains the label associated with the intended \bibitem, which is located inside a thebibliography environment, and contains the reference data. Both corresponding \bibitem and \cite must have the same {key}; the easiest way to organise keys is by the author's last name. The secondary braces in the thebibliography environmen denote the longest bibliography label you expect to have. So, inserting {foo} means you can have any label shorter or as large as the expression foo. Failure to set this parameter correctly may result in a not so attractive indentation of your bybliography.

The bibliography is a section apart from your main document, and an example of code for the bibliography would look like the following:

		\begin{thebibliography}{50}
		\bibitem{Simpson} Homer J. Simpson. \textsl{Mmmmm...doughnuts}.
		Evergreen Terrace Printing Co., Springfield, SomewhereUSA, 1998
		\end{thebibliography)

Then, your main source code would contain the location of the information relating to the \bibitem using \cite. That source code would look similar to this:

		My thesis, about the philosophy of The Simpsons\copyright
		comes from my favorite book \cite{Simpson}.

As it is often difficult to remember the exact citation key once you have many references, Kile provides an easy way to insert a citation. On the Edit toolbar click on the second drop-down box (usually it reads label) and select cite. A list with all the citation keys will show: select the correct reference and a citation will be inserted in your document. To update the list of keys, either save the file or choose Edit->Refresh Structure.

The final product in your document's bybliography would then look like this:

[1] Homer J. Simpson. Mmmmm...doughnuts. Evergreen Terrace Printing Co., Springfield, SomewhereUSA, 1998.

The easiest way to work with \bibitem and \cite is to use the toolbar drop-down box marked cite. When you select a citation to insert, you will be given the list of bibitems you have created so far, and will be able to select the reference from the list. Kile can also work together with BibT_EX editor applications, such as gBib and pyBliographer, to help make citations easier.