As mentioned in Combining citations at some instance, you are looks for the functionality of mciteplus. This requires a suitable bibliography style and some slight modifications to standard input. As you are using IEEEtran as your bibliography style things are easy: there is an 'out of the box' style to work with mciteplus for this:
\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@article{Renchan2003,
author = {Renchan, E. D.},
journal = {Proc. Inf. Conf. Computer-Aided Design},
pages = {123-126},
title = {{UBKSS}: realizable reduction in extracted PL circuits},
year = {2003},
}
@techreport{Shuangle2004,
author = {Shuangle, W.},
institution = {National University, Department of Computer Science},
pages = {304-309},
number = {RN-CS-99-03},
title = {The high algorithm},
year = {2004},
}
@article{Wang2007,
author = {Wang, F. M.},
journal = {IEEE Trans. Electron Devices},
pages = {304-309},
title = {Analysis and synthesis of on chip spiral inductors},
volume = {36},
year = {2007},
}
\end{filecontents*}
\documentclass{article}
\usepackage{mciteplus}
% Turn on mciteplus sublists
\mciteSetSublistMode{s}
% Make the sublists simply create new paragraphs
\mciteSetSublistLabelBeginEnd{\par}{\relax}{\relax}
\mciteSetMidEndSepPunct
{\ifmciteBstWouldAddEndPunct.\else\fi\space}
{\ifmciteBstWouldAddEndPunct.\else\fi}
{\relax}
\begin{document}
\cite{Renchan2003,*Wang2007,Shuangle2004}
\bibliographystyle{IEEEtranM}
\bibliography{\jobname}
\end{document}
Notice that I've prefixed the 'subentry' citation with a star: that's required for mciteplus to know to combine entries. I've also set up the 'sublist' to simply print each entry on a new line.
If you want to use natbib along with mciteplus there is a IEEEtranMN style for that.
[1])? – Mico Oct 29 '14 at 06:55biblatex. – Joseph Wright Oct 29 '14 at 07:14