在進行調查和系統性文獻綜述時，我們參考和初級研究：審查中正在分析和審查的研究。兩者都需要在文件中引用。
有沒有辦法在乳膠文件中擁有兩種單獨的參考樣式來區分參考和主要研究？例如，我們應該有類似以下簡單範例的內容：
In this review, we followed the procedures introduced in our earlier
work in [1] and [2] and extended by Heisenberg and Pinkman in [3] to analyse the
primary studies [PS1], [PS2], and [PS3].
References:
[1] Reference 1
[2] Reference 2
[3] Reference 3
Primary studies:
[PS1] Primary Study 1
[PS2] Primary Study 2
[PS3] Primary Study 3
更新：2017 年 2 月 1 日
根據評論我嘗試了這個包splitbib。我嘗試了中提供的相同的程式碼包文件，但我收到以下錯誤：
! File ended while scanning use of \@bibitem.
<inserted text>
\par
<*> test.tex
I suspect you have forgotten a `}', causing me
to read past where you wanted me to stop.
I'll try to recover; but if the error is serious,
you'd better type `E' or `X' now and fix your file.
當我運行腳本時：
\documentclass{article}
\usepackage{splitbib}
\begin{category}[A]{First category}
\SBentries{entry1,entry4}
\end{category}
\begin{category}[B]{Second category}
\begin{category}{First sub-category}
\SBentries{entry2,entry6}
\end{category}
\begin{category}{Second sub-category}
\SBentries{entry5,entry3}
\end{category}
\end{category}
\begin{document}
We cite~\cite{entry1,entry3,entry4,entry5}. Note that we cite neither
\verb+entry2+ nor \verb+entry6+,even though they have been assigned a category. defined in the last category. The first
sub-category will then not appear in the bibliography.
% \def\SBlongestlabel{A1}
\SBtitlestyle{bar}
\SBsubtitlestyle{none}
\begin{thebibliography}{1}
\bibitem{entry1} This is the first entry.
\bibitem{entry3} This is the third entry.
\bibitem{entry4} This is the fourth one.
\bibitem{entry5} This is the last one.
\end{thebibliography}
\end{document}