\documentclass{article}% or book, report, ...
\begin{document}
See \cite{citeA} or \cite{citeB} or \cite{citeA, citeB}.
\begin{thebibliography}{x}
% \bibitem{<biblabel>} <citation>
\bibitem{citeA}
{\scshape Author, A}, {\itshape A title}, Journal of So-and-So, 2000.
\bibitem{citeB}
{\scshape Someone, B}, {\itshape Another title}, Book of books, 1900.
\end{thebibliography}
\end{document}
Note that unless you really know why, you should probably not do this. Using designated packages (see other examples) is preferable.