main.bbl

\begin{thebibliography}{20}
\newcommand{\enquote}[1]{``#1''}
\expandafter\ifx\csname natexlab\endcsname\relax\def\natexlab#1{#1}\fi
\expandafter\ifx\csname url\endcsname\relax
  \def\url#1{\texttt{#1}}\fi
\expandafter\ifx\csname urlprefix\endcsname\relax\def\urlprefix{URL }\fi
\providecommand{\eprint}[2][]{\url{#2}}

\bibitem[{胡运权(2007)}]{Op07}
胡运权 (2007).
\newblock \emph{运筹学教程}.
\newblock 清华大学出版社, 第三版 edition.
\newblock ISBN 978-7-302-14738-1.

\bibitem[{Berkelaar \emph{et~al.}(2008)}]{lpSolve08}
Berkelaar M, \emph{et~al.} (2008).
\newblock \emph{lpSolve: Interface to Lp\_solve v.5.5 to solve linear/integer
  programs}.
\newblock R package version 5.6.4.

\bibitem[{Csardi and Nepusz(2006)}]{igraph06}
Csardi G, Nepusz T (2006).
\newblock \enquote{The igraph software package for complex network research.}
\newblock \emph{InterJournal}, \textbf{Complex Systems}, 1695.
\newblock \urlprefix\url{http://igraph.sf.net}.

\bibitem[{Hahsler and Hornik(2008)}]{TSP08}
Hahsler M, Hornik K (2008).
\newblock \emph{TSP: Traveling Salesperson Problem (TSP)}.
\newblock R package version 0.2-4,
  \urlprefix\url{http://r-forge.r-project.org/projects/tsp/}.

\bibitem[{Lewin-Koh \emph{et~al.}(2008)Lewin-Koh, Bivand, contributions~by
  Edzer J.~Pebesma, Archer, Dray, Forrest, Giraudoux, Golicher, Rubio,
  Hausmann, Jagger, Luque, MacQueen, Niccolai, and Short}]{maptools08}
Lewin-Koh NJ, Bivand R, contributions~by Edzer J~Pebesma, Archer E, Dray S,
  Forrest D, Giraudoux P, Golicher D, Rubio VG, Hausmann P, Jagger T, Luque SP,
  MacQueen D, Niccolai A, Short T (2008).
\newblock \emph{maptools: Tools for reading and handling spatial objects}.
\newblock R package version 0.7-15.

\bibitem[{Minka(2008)}]{maps08}
Minka TP (2008).
\newblock \emph{maps: Draw Geographical Maps}.
\newblock R package version 2.0-40.

\bibitem[{Novomestky(2008)}]{goalprog08}
Novomestky F (2008).
\newblock \emph{goalprog: Weighted and lexicographical goal programming and
  optimization}.
\newblock R package version 1.0-2.

\bibitem[{{R Development Core Team}(2008)}]{R08}
{R Development Core Team} (2008).
\newblock \emph{R: A Language and Environment for Statistical Computing}.
\newblock R Foundation for Statistical Computing, Vienna, Austria.
\newblock {ISBN} 3-900051-07-0, \urlprefix\url{http://www.R-project.org}.

\bibitem[{Tamura(2007)}]{Rdonlp207}
Tamura R (2007).
\newblock \emph{Rdonlp2: an R extension library to use Peter Spelluci's DONLP2
  from R.}
\newblock R package version 0.3-1, \urlprefix\url{http://arumat.net/Rdonlp2/}.

\bibitem[{Tendys(2002)}]{gafit02}
Tendys T (2002).
\newblock \emph{gafit: Genetic Algorithm for Curve Fitting}.
\newblock R package version 0.4,
  \urlprefix\url{http://www.progsoc.uts.edu.au/~telford/}.

\bibitem[{Theussl and Hornik(2008)}]{Rglpk08}
Theussl S, Hornik K (2008).
\newblock \emph{Rglpk: R/GNU Linear Programming Kit Interface}.
\newblock R package version 0.2-5,
  \urlprefix\url{http://R-Forge.R-project.org/projects/rglp/,
  http://www.gnu.org/software/glpk/}.

\bibitem[{Winston(2007)}]{OP06}
Winston WL (2007).
\newblock \emph{运筹学--应用范例与解法}.
\newblock 清华大学出版社, 第四版 edition.
\newblock ISBN 7-302-13208-9/TP·8347.

\end{thebibliography}