What is the correct way to cite the following:
[2, and the references therein] [see also 13,15,33]
Should there be a comma after see also? And what is the command to produce it?
The package natbib redefines the \citecommand with optional arguments that do exactly what you are asking for. Here is an example:
\documentclass{article}
\usepackage{filecontents}
\usepackage[numbers]{natbib}
\begin{filecontents}{biblio.bib}
@article{Author2012,
Author = {Author, A},
Title = {Article},
Year = {2012}}
\end{filecontents}
\begin{document}
\cite{Author2012}
\cite[e.g.]{Author2012}
\cite[see][]{Author2012}
\cite[and references therein]{Author2012}
\cite[see][and references therein]{Author2012}
\bibliographystyle{plainnat}
\bibliography{biblio}
\end{document}
The output looks like this:

If you prefer author-year citation style, you can remove the [numbers] option when loading the package, and you can replace the square brackets by round brackets with the option [round].
natbib: \cite[Ch.~1]{Author2012} gives [1, Ch. 1] and \cite[p.~387]{Author2012} gives [1, p. 387]. Any words not relating to the citation should be kept outside the square brackets, see @percusse's comment above.
– Alex
Sep 06 '12 at 12:36
(see also \cite{ref1, ref2, ref3})– Alex Sep 06 '12 at 09:47[2, and the references therein]conventionally refers to the study [2] and in it the Section, Chapter, or Theorem etc. which is called and the references therein. – percusse Sep 06 '12 at 10:58