\begin{thebibliography}{CdJ02}

\bibitem[Art69]{Artin}
Michael Artin.
\newblock Algebraization of formal moduli. {I}.
\newblock In {\em Global Analysis (Papers in Honor of K. Kodaira)}, pages
  21--71. Univ. Tokyo Press, Tokyo, 1969.

\bibitem[Art74]{ArtinVersal}
M.~Artin.
\newblock Versal deformations and algebraic stacks.
\newblock {\em Inventiones Mathematics}, 27:165--189, 1974.

\bibitem[CdJ02]{ConradeJong}
B.~Conrad and A.J. de~Jong.
\newblock Approximation and versal deformations.
\newblock {\em Journal of Algebra}, 255:489--515, 2002.

\bibitem[DM69]{DM}
P.~Deligne and D.~Mumford.
\newblock The irreducibility of the space of curves of given genus.
\newblock {\em Publ. Math. IHES}, 36:75--110, 1969.

\bibitem[KM97]{K-M}
Se{\'a}n Keel and Shigefumi Mori.
\newblock Quotients by groupoids.
\newblock {\em Ann. of Math. (2)}, 145:193--213, 1997.

\end{thebibliography}