\begin{thebibliography}{1}

\bibitem{elworthy94}
K.~D. Elworthy, W.~N. Everitt, and E.~B. Lee, editors.
\newblock {\em Differential Equations, Dynamical Systems, and Control Science:
  {A} Festschrift in Honor of Lawrence Markus}.
\newblock Marcel Dekker, Inc., New York, 1994.
\newblock Lecture Notes in Pure and Applied Mathematics, Vol. 152.

\bibitem{leigh83}
J.~R. Leigh.
\newblock {\em Modelling and Simulation}.
\newblock IEE Topics in Control Series 1. Peter Peregrinus Ltd., London, 1983.

\bibitem{rd91}
{Reader's Digest Practical Problem Solver}.
\newblock {S}ubstitutes, {S}hortcuts, and {I}ngenious {S}olutions for {M}aking
  {L}ife {E}asier.
\newblock The Reader's Digest Association, Inc., Pleasantville, New York, 1991.

\end{thebibliography}
