vis_art.bbl
\providecommand{\bysame}{\leavevmode\hbox to3em{\hrulefill}\thinspace}
\providecommand{\MR}{\relax\ifhmode\unskip\space\fi MR }
% \MRhref is called by the amsart/book/proc definition of \MR.
\providecommand{\MRhref}[2]{%
  \href{http://www.ams.org/mathscinet-getitem?mr=#1}{#2}
}
\providecommand{\href}[2]{#2}
\begin{thebibliography}{EPY97}

\bibitem[Cai83]{u-Cai83}
Francis Cailliez, \emph{The analytical solution of the additive constant
  problem}, Psychometrika \textbf{48} (1983), no.~2, 305\NDASH 308.

\bibitem[EPY97]{u-EPY97}
David Eppstein, M.~S. Paterson, and F.~F. Yao, \emph{On nearest-neighbor
  graphs}, Discrete Comput. Geom. \textbf{17} (1997), 263\NDASH 282.

\bibitem[FT43]{u-Fej43}
L.~Fejes~T{\'o}th, \emph{Absch{\"a}tzung des k{\"u}rzesten {A}bstandes zweier
  {P}unkte eines auf der {K}ugelfl{\"a}che liegenden {P}unktsystems},
  Jahresberichte Deutsch. Math.-Ver. \textbf{53} (1943), 66\NDASH 68.

\bibitem[Hei98]{u-Hei98}
Jobst Heitzig, \emph{Partially ordered monoids and distance functions}, Diploma
  thesis, Universit{\"a}t Hannover, Germany, July 1998.

\bibitem[Hei02]{u-Hei01}
\bysame, \emph{Many familiar categories can be interpreted as categories of
  generalized metric spaces}, Appl.\ Categ.\ Structures {\rm (to appear)}
  (2002).

\bibitem[KG90]{u-KG90}
Maurice Kendall and Jean~Dickinson Gibbons, \emph{Rank correlation methods},
  5th ed., Edward Arnold, London, 1990.

\bibitem[Kre91]{u-Kre91}
Ulrich Krengel, \emph{Einf{\"u}hrung in die {W}ahrscheinlichkeitstheorie und
  {S}tatistik}, 3rd ed., Vieweg, Braunschweig, 1991.

\bibitem[Men28]{u-Men28}
Karl Menger, \emph{Untersuchungen {\"u}ber allgemeine {M}etrik}, Math. Annalen
  \textbf{100} (1928), 75\NDASH 163.

\bibitem[PT86]{u-PT86}
Svatopluk Poljak and Daniel Turz{\'\i}k, \emph{A polynomial time heuristic for
  certain subgraph optimization problems with guaranteed worst case bound},
  Discr. Math. \textbf{58} (1986), 99\NDASH 104.

\bibitem[She62]{u-She62}
Roger~N. Shepard, \emph{The analysis of proximities: multidimensional scaling
  with an unknown distance function. {I}}, Psychometrika \textbf{27} (1962),
  125\NDASH 140.

\end{thebibliography}
