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\title{Can we use May's ideas to minimise risk in the financial system?}
\author{Thomas Castle}
\date{\today}
\begin{document}
\maketitle
\section{Introduction}
In 1972, Robert May made major advancements in population biology using mathematical techniques, determining that the stability of ecological networks decreases if the network is sufficiently large or complex after writing a paper in Nature (May, 1972) \cite{nat}. His work suggests that complex food webs within real ecosystems should not persist, although there exists many ecosystems with a large population of interacting species. Since then May's work has been extended to introduce various other variables including mutualistic relationships and nestedness which have been used to explain why such large systems may not just exist but also thrive. The applications of May's ideas are not just confined to population growth in ecosystems, his work has been used in the field of biodiversity and the study of diseases. More recently May wrote an article in Nature regarding risks in the financial system and relating his work on the dynamics of ecological food webs with the complexity and stability in models of finiancial networks(May \& Haldane, 2011) \cite{ban2}. Even if our financial system reflects May's ideas on multi specie communities and is inherently unstable,the concepts behind his work may be able to minimise systematic risks in the ecosystem of our economy.
\section{A summary of May's ideas}
\begin{thebibliography}{99}
\bibitem{nat} May, R.M. (1972). Will a Large Complex System be Stable?. \textit{Nature}. 238. pp.413--414.
\bibitem{ban} May, R.M \& Haldane, A.G. (2011). Systematic risk in the banking ecosystems. \textiy{Nature}. 469. pp.351--355.
\end{thebibliography}
\end{document}
答案1
一些评论：
文献正文为
\cite{ban2}，但引文关键词为ban。这一点必须协调。\textiy应该是\textit吧？我会将“finiancial”改为“financial”。:-)
最后但并非最不重要的一点是，您似乎希望使用您手动构建的
thebibliography环境创建括号样式的作者年份类型的引文标注。如果是这样，我建议您 (a) 加载natbib引文管理包和 (b) 为每个条目提供一个可选参数\bibitem，如下例所示。这样，您就可以使用它\citep来创建括号样式的引文标注。
\documentclass[a4paper,12pt]{amsart}
%% I've streamlined the preamble to focus on the relevant parts
\usepackage[round,authoryear]{natbib}
\usepackage[colorlinks,citecolor=blue]{hyperref} % just for this example
\begin{document}
\dots\ a paper in \emph{Nature} \citep{nat}. \dots
\dots\ in models of financial networks \citep{ban}. \dots
\begin{thebibliography}{99}
\bibitem[May(1972)]{nat} May, R.M. (1972). Will a Large Complex
System be Stable? \textit{Nature}. 238. pp.~413--414.
\bibitem[May~\& Haldane(2011)]{ban} May, R.M. \& Haldane, A.G.
(2011). Systematic risk in the banking ecosystems. \textit{Nature}.
469. pp.~351--355.
\end{thebibliography}
\end{document}