\begin{thebibliography}{1}

\bibitem{toldi85}
J.~L. Toldi.
\newblock {\em Velocity analysis without picking}.
\newblock PhD thesis, Stanford University, 1985.

\bibitem{Toldi89}
J.~L. Toldi.
\newblock Velocity analysis without picking.
\newblock {\em Geophysics}, 54(2):191--199, 1989.

\bibitem{lin:pick}
L.~Zhang.
\newblock Automatic picking and its applications.
\newblock {\em Stanford Exploration Project Report,
  http://sepwww.stanford.edu/\urlbr{}research/\urlbr{}reports/}, 70:275--292,
  1991.

\end{thebibliography}