Journal of Mathematical Sciences: Advances and Applications[1] A. A. Agrachev, Canonical Nilpotentization of Control Systems,
Preprint, 1997 (3 pages).
[2] A. A. Agrachev, R. V. Gamkrelidze and A. V. Sarychev, Local
invariants of smooth control systems, Acta Appl. Math. 14 (1989),
191-237.
[3] A. A. Agrachev and A. V. Sarychev, Filtrations of a Lie algebra of
vector fields and nilpotent approximation of control systems, Dokl.
Akad. Nauk SSSR 295 (1987); English transl. in Soviet Math. Dokl. 36
(1988), 104-108.
[4] A. A. Agrachev and A. Marigo, Nonholonomic tangent spaces:
Intrinsic construction and rigid dimensions, Electronic Res. Announc.
Amer. Math. Soc. 9 (2003), 111-120.
[5] A. A. Agrachev and A. Marigo, Rigid Carnot algebras: A
classification, J. Dynam. Control Syst. 11 (2005), 449-494.
[6] A. Bellaïche, The tangent space in sub-Riemannian geometry, in:
A. Bellaïche and J.-J. Risler (Eds.), Sub-Riemannian Geometry,
Birkhäuser, 1996, 1-78.
[7] R. M. Bianchini and G. Stefani, Graded approximations and
controllability along a trajectory, SIAM J. Control Optimiz. 28
(1990), 903-924.
[8] H. Hermes, Nilpotent approximations of control systems and
distributions, SIAM J. Control Optimiz. 24 (1986), 731-736.
[9] H. Hermes, Nilpotent and high-order approximations of vector field
systems, SIAM Review 33 (1991), 238-264.
[10] G. Sklyar and S. Yu. Ignatovich, Description of all privileged
coordinates in the homogeneous approximation problem for nonlinear
control systems, C. R. Acad. Sci. Paris, Sér. I 344 (2007),
109-114.
[11] G. Sklyar and S. Yu. Ignatovich, Fliess series, a generalization
of Ree’s theorem, and an algebraic approach to the homogeneous
approximation problem, Int. J. Control 81 (2008), 369-378.
[12] F. Jean, The car with N trailers: Characterization of the
singular configurations, ESAIM: Control, Optimization and Calculus of
Variations 1 (1996), 241-266 (electronic).
[13] A. Kumpera and C. Ruiz, Sur l’équivalence locale des systèmes
de Pfaff en drapeau, in: F. Gherardelli (Ed.), Monge-Ampère Equations
and Related Topics, Ist. Alta Math. F. Severi, Rome, 1982, 201-248.
[14] R. Montgomery and M. Zhitomirskii, Geometric approach to Goursat
flags, Ann. Inst. H. Poincaré - AN 18 (2001), 459-493.
[15] R. Montgomery and M. Zhitomirskii, Points and Curves in the
Monster Tower, Memoirs Amer. Math. Soc. 956, AMS, Providence, 2010.
[16] P. Mormul, Local classification of rank-2 distributions
satisfying the Goursat condition in dimension 9, in: P. Orro and F.
Pelletier (Eds.), Singularités et Géométrie sous-riemannienne,
Collection Travaux en cours 62, Hermann, 2000, 89-119.
[17] P. Mormul, Goursat flags: Classification of codimension-one
singularities, J. Dynam. Control Syst. 6 (2000), 311-330.
[18] P. Mormul, Goursat distributions not strongly nilpotent in
dimensions not exceeding seven, in: A. Zinober and D. Owens (Eds.),
Nonlinear and Adaptive Control, Lecture Notes in Control and Inform.
Sci. 281, Springer, 2003, 249-261.
[19] P. Mormul, Real moduli in local classification of Goursat flags,
Hokkaido Math. J. 34 (2005), 1-35.
[20] P. Mormul, Kumpera-Ruiz algebras in Goursat flags are optimal in
small lengths, J. Math. Sciences 126 (2005), 1614-1629.
[21] P. Mormul, Do moduli of Goursat distributions appear on the level
of nilpotent approximations?, in: J.-P. Brasselet and M. A. S. Ruas
(Eds.), Real and Complex Singularities (Trends in Mathematics),
Birkhäuser, 2006, 229-246.
[22] L. P. Rothschild and E. M. Stein, Hypoelliptic differential
operators and nilpotent groups, Acta Math. 137 (1976), 247-320.
