\providecommand{\bysame}{\leavevmode\hbox to3em{\hrulefill}\thinspace}
\begin{thebibliography}{GrLie4-6}

\bibitem[BGG73]{BGG}
I.~N. Bernstein, I.~M. Gelfand, and S.~I. Gelfand, \emph{Schubert cells, and
  the cohomology of the spaces ${G}/{P}$}, Uspehi Mat. Nauk \textbf{28} (1973),
  no.~3(171), 3--26.

\bibitem[BL00]{B-L}
S.~Billey and V.~Lakshmibai, \emph{Singular loci of {S}chubert varieties},
  Progress in Mathematics, vol. 182, Birkh{\"a}user Boston Inc., Boston, MA,
  2000.

\bibitem[Ch94]{Ch}
C.~Chevalley, \emph{Sur les d{\'e}compositions cellulaires des espaces
  {$G/B$}}, Algebraic groups and their generalizations: classical methods
  (University Park, PA, 1991), Proc. Sympos. Pure Math., vol.~56, Amer. Math.
  Soc., Providence, RI, 1994, With a foreword by Armand Borel, pp.~1--23.

\bibitem[Ek87]{E}
T.~Ekedahl, \emph{On supersingular curves and abelian varieties}, Math. Scand.
  \textbf{60} (1987), 151--178.

\bibitem[FC90]{F-C}
G.~Faltings and C.-L. Chai, \emph{Degeneration of abelian varieties.},
  Ergebnisse der Math., no.~22, Springer Verlag, 1990.

\bibitem[FP98]{F-P}
W.~Fulton and P.~Pragacz, \emph{Schubert varieties and degeneracy loci}, SLN,
  vol. 1689, Springer-Verlag, Berlin, 1998, Appendix J by the authors in
  collaboration with I. Ciocan-Fontanine.

\bibitem[Fu96]{Fu2}
W.~Fulton, \emph{Determinantal formulas for orthogonal and symplectic
  degeneracy loci}, J. Differential Geom. \textbf{43} (1996), no.~2, 276--290.

\bibitem[Ful]{Ful}
\bysame, \emph{Intersection theory}, vol.~3, Ergebnisse der Mathematik und
  ihrer Grenzgebiete, no.~2, Springer Verlag, 1984.

\bibitem[Ge99]{vdG1}
G.~van~der Geer, \emph{Cycles on the moduli space of abelian varieties}, Moduli
  of curves and abelian varieties (C.~Faber and E.~Looijenga, eds.), Aspects
  Math., E33, Vieweg, Braunschweig, 1999, pp.~65--89.

\bibitem[GrLie4-6]{Bou}
N.~Bourbaki, \emph{Groupes et alg{\`e}bres de {L}ie. {IV}--{VI}}, Hermann,
  Paris, 1968.

\bibitem[HW61]{hasse63::zyklis+erweit+primz+funkt+charak}
H.~Hasse and E.~Witt, \emph{Zyklische unverzweigte {E}rweiterungsk{\"o}rper von
  primzahlgrade {$p$} {\"u}ber einem algebraischen {F}unktionenk{\"o}rper der
  {C}harakteristik {$p$}}, Monatsh. Math. Phys. \textbf{43} (1963), 477--492.

\bibitem[Ha07]{harashita07::ekedah+oort+newton}
S.~Harashita, \emph{Ekedahl-{O}ort strata and the first {N}ewton slope strata},
  J. of Algebraic Geom. \textbf{16} (2007), no.~1, 171--199.

\bibitem[Jo93]{Jo}
A.~J. de~Jong, \emph{The moduli spaces of principally polarized abelian
  varieties with {$\Gamma\sb 0(p)$}-level structure}, J. of Algebraic Geom.
  \textbf{2} (1993), no.~4, 667--688.

\bibitem[KS03]{K-S}
S.~Keel and L.~Sadun, \emph{Oort's conjecture for {$A\sb g\otimes\mathbb C$}},
  J. Amer. Math. Soc. \textbf{16} (2003), no.~4, 887--900 (electronic).

\bibitem[KT02]{kresch02::doubl+schub}
A.~Kresch and H.~Tamvakis, \emph{Double {S}chubert polynomials and degeneracy
  loci for the classical groups}, Ann. Inst. Fourier (Grenoble) \textbf{52}
  (2002), no.~6, 1681--1727.

\bibitem[M2]{M2}
D.~R. Grayson and M.~E. Stillman, \emph{Macaulay 2, a software system for
  research in algebraic geometry}, Available at
  \url{http://www.math.uiuc.edu/Macaulay2}.

\bibitem[MB81]{M-B2}
L.~Moret-Bailly, \emph{Familles de courbes et vari{\'e}t{\'e}s ab{\'e}liennes
  sur {$\mathbb P^1$}.}, S{\'e}minaire sur les pinceaux de courbes de genre au
  moins deux. (L.~Szpiro, ed.), Ast{\'e}risque, vol.~86, Soc. math. de France,
  1981, pp.~109--140.

\bibitem[MB85]{M-B}
\bysame, \emph{Pinceaux de vari{\'e}t{\'e}s ab{\'e}liennes}, Ast{\'e}risque
  (1985), no.~129, 266.

\bibitem[MW04]{moonen04::discr}
B.~Moonen and T.~Wedhorn, \emph{Discrete invariants of varieties in positive
  characteristic}, IMRN (2004).

\bibitem[Mo01]{moonen01::group+weyl}
B.~Moonen, \emph{Group schemes with additional structures and {W}eyl group
  cosets}, Moduli of abelian varieties (Texel Island, 1999), Progr. Math., vol.
  195, Birkh{\"a}user, Basel, 2001, pp.~255--298.

\bibitem[Mu70]{Mu}
D.~Mumford, \emph{Abelian varieties}, Tata Institute of Fundamental Research
  Studies in Mathematics, vol.~5, Oxford University Press., London, 1970.

\bibitem[Oo01]{O1}
F.~Oort, \emph{A stratification of a moduli space of abelian varieties}, Moduli
  of abelian varieties (Texel Island, 1999), Progr. Math., vol. 195,
  Birkh{\"a}user, Basel, 2001, pp.~345--416.

\bibitem[Oo95]{O}
\bysame, \emph{Complete subvarieties of moduli spaces}, Abelian varieties
  (Egloffstein, 1993), de Gruyter, Berlin, 1995, pp.~225--235.

\bibitem[PR97]{P-R}
P.~Pragacz and J.~Ratajski, \emph{Formulas for {L}agrangian and orthogonal
  degeneracy loci; {$\tilde Q$}-polynomial approach}, Compositio Math.
  \textbf{107} (1997), no.~1, 11--87.

\bibitem[PR99]{PR99}
H.~Pittie and A.~Ram, \emph{A {P}ieri-{C}hevalley formula in the {$K$}-theory
  of a {$G/B$}-bundle}, Electron. Res. Announc. Amer. Math. Soc. \textbf{5}
  (1999), 102--107 (electronic).

\bibitem[Pr91]{P}
P.~Pragacz, \emph{Algebro-geometric applications of {S}chur {$S$}- and
  {$Q$}-polynomials}, Topics in invariant theory (Paris, 1989/1990), Lecture
  Notes in Math., vol. 1478, Springer, Berlin, 1991, pp.~130--191.

\bibitem[RR85]{ramanan85::projec+schub}
S.~Ramanan and A.~Ramanathan, \emph{Projective normality of flag varieties and
  {S}chubert varieties}, Invent. Math. \textbf{79} (1985), no.~2, 217--224.

\bibitem[S]{S}
N.~Sloane, \emph{The on-line encyclopedia of integer sequences},
  \url{http://www.research.att.com/~njas/sequences}.

\bibitem[Sj07]{sjoestrand::bruhat+ferrer}
J.~Sj{\"o}strand, \emph{Bruhat intervals as rooks on skew ferrers boards}, To
  appear in J. Combin. Theory Ser. A, \eprint{math.CO/0601615}.

\end{thebibliography}