]. R. Abraham and J. Marsden, The stratification of proper groupoids Bibliography, Foundations of Mechanics, issue.1, 1978.

R. Abraham, J. Marsden, and T. S. Ratiu, Manifolds, Tensor Analysis and Applications, Applied Mathematical Sciences, vol.75, 1988.
DOI : 10.1063/1.2916250

C. Albert, Le th??or??me de r??duction de Marsden-Weinstein en g??om??trie cosymplectique et de contact, Journal of Geometry and Physics, vol.6, issue.4, pp.627-649, 1989.
DOI : 10.1016/0393-0440(89)90029-6

V. I. Arnold, Sur la géométrie différentielle des groupes de Lie de dimension infinie et ses applicationsàcationsà l'hydrodynamique des fluids parfaits, pp.16-319, 1966.

V. I. Arnold, Mathematical Methods of Classical Mechanics, 1984.

A. Bejancu, The geometry of CR submanifolds Mathematics and its Applications, 1986.

D. E. Blair, Riemannian geometry of contact and symplectic manifolds, Progress in Math. 203, Birkhäuser, 2002.

C. P. Boyer and K. Galicki, ON SASAKIAN???EINSTEIN GEOMETRY, International Journal of Mathematics, vol.11, issue.07, pp.873-909, 2000.
DOI : 10.1142/S0129167X00000477

C. P. Boyer and K. Galicki, 3-Saskian Manifolds Surveys in differential geometry: essays on Einstein manifolds, Surv. Diff. Geom, pp.123-184, 1999.

R. L. Bryant, An Introduction to Lie Groups and Symplectic Geometry. Geometry and quantum field theory, IAS/Park City Math. Ser, vol.1, pp.5-181, 1991.

E. Calabi, Extremal Kähler Metrics II, Differential Geometry and Complex Analysis, pp.95-114, 1985.

O. M. Dragulete and L. Ornea, Non-zero contact and Sasakian reduction, Differential Geometry and its Applications, vol.24, issue.3, pp.260-270, 2006.
DOI : 10.1016/j.difgeo.2005.09.003

O. Dr?-agulete, L. Ornea, and T. S. Ratiu, Cosphere bundle reduction in contact geometry, . Symplectic Geom, pp.695-714, 2003.

J. J. Duistermaat and J. A. Kolk, Lie Groups, 2000.
DOI : 10.1007/978-3-642-56936-4

T. Ekholm and J. B. Etnyre, Invariants of Knots, Embeddings and Immersions via Contact Geometry, math, p.412517

A. Futaki, Kähler-Einstein Metrics and Integral Invariants, Lecture Notes in Mathematics, vol.1314, 1988.
DOI : 10.1007/bfb0078084

A. Futaki, The Ricci curvature of symplectic quotients of Fano manifolds, Tohoku Mathematical Journal, vol.39, issue.3, pp.329-339, 1987.
DOI : 10.2748/tmj/1178228281

H. Geiges, Constructions of contact manifolds, Mathematical Proceedings of the Cambridge Philosophical Society, vol.121, issue.3, pp.455-464, 1997.
DOI : 10.1017/S0305004196001260

H. Geiges, A brief history of contact geometry and topology, Expositiones Mathematicae, vol.19, issue.1, pp.25-53, 2001.
DOI : 10.1016/S0723-0869(01)80014-1

G. Grantcharov and L. Ornea, Reduction of Sasakian manifolds, Journal of Mathematical Physics, vol.42, issue.8, pp.3808-3816, 2001.
DOI : 10.1063/1.1386636

V. Guillemin and S. Sternberg, Homogeneous quantization and multiplicities of group representations, Journal of Functional Analysis, vol.47, issue.3, pp.344-380, 1982.
DOI : 10.1016/0022-1236(82)90111-2

Y. Hatakeyama, Some notes on differentiable manifolds with almost contact structures, Tôhuku Math, J, vol.15, pp.176-181, 1963.

V. A. Iskovskikh and Y. G. Prokhorov, Fano varieties, in Algebraic geometry, V, Encyclop, Math. Sci, vol.47, pp.1-247, 1999.

Y. Kamishima and L. Ornea, Geometric flow on compact locally conformally K??hler manifolds, Tohoku Mathematical Journal, vol.57, issue.2, pp.201-221, 2005.
DOI : 10.2748/tmj/1119888335

A. A. Kirillov, Elements of the Theory of Representations, Grundlehren der mathematischen Wissenschaften, 1976.

A. A. Kirillov, The orbit method. I. Geometric quantization, Contemporary Mathematics, vol.145, pp.1-63, 1983.
DOI : 10.1090/conm/145/1216179

S. Kobayashi, Submersions of CR submanifolds, Tohoku Math, J, vol.39, pp.95-100, 1987.

B. Kostant, Orbits, Symplectic Structures and Representation Theory, Proc. US-Japan Seminar on Diff. Gem, p.77, 1965.
DOI : 10.1007/b94535_20

B. Kostant, On differential geometry and homogenous spaces II, Proc, vol.42, pp.354-357, 1956.
DOI : 10.1007/b94535_6
URL : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC528290

E. Lerman, Contact cuts, Israel Journal of Mathematics, vol.73, issue.1, pp.77-92, 2001.
DOI : 10.1007/BF02772608

E. Lerman and C. Willett, The topological structure of contact and symplectic quotients, Internat. Math. Res. Notices, vol.1, pp.33-52, 2001.

F. Loose, Reduction in contact geometry, J. Lie Theory, vol.11, issue.1, pp.9-22, 2001.

J. E. Marsden and T. S. Ratiu, Introduction to Mechanics and Symmetry, Springer Texts in Appl, Math, vol.17, 2003.

J. E. Marsden and A. Weinstein, Reduction of symplectic manifolds with symmetry, Reports on Mathematical Physics, vol.5, issue.1, pp.121-130, 1974.
DOI : 10.1016/0034-4877(74)90021-4

D. Mcduff and D. Salamon, Introduction to symplectic topology, 1998.

R. Mclachan and M. Perlmutter, Conformal Hamiltonian systems, Journal of Geometry and Physics, vol.39, issue.4, pp.276-300, 2001.
DOI : 10.1016/S0393-0440(01)00020-1

I. Moerdijk and J. Mr?un, Introduction to Foliations and Lie Groupoids, Cambridge Studies in advanced mathematics, p.91, 2003.

R. Nagem and G. H. Sandri, Canonical Transformation and Phase Trajectories of the Damped Harmonic oscillator, Journal of Sound and Vibration, vol.169, issue.2, pp.270-275, 1994.
DOI : 10.1006/jsvi.1994.1527

J. P. Ortega, Some remarks about the geometry of Hamiltonian conservation laws, Symmetry and Perturbation Theory, pp.162-170

J. Ortega and T. R. Ratiu, Momentum Maps and Hamiltonian Reduction, Progress in Mathematics, vol.222, 2004.
DOI : 10.1007/978-1-4757-3811-7

R. S. Palais, On the Existence of Slices for Actions of Non-Compact Lie Groups, The Annals of Mathematics, vol.73, issue.2, pp.295-323, 1961.
DOI : 10.2307/1970335

N. Papaghiuc, Submersions of semi-invariant submanifolds of a Sasakian manifold, An. S ¸tiint¸.¸tiint¸. Univ, Al. I. Cuza Ia¸siIa¸si Sect¸.Sect¸. I Mat, vol.35, pp.281-288, 1989.

M. Perlmutter, M. Rodríguez-olmos, and M. E. Sousa-dias, On the geometry of reduced cotangent bundles at zero momentum, Journal of Geometry and Physics, vol.57, issue.2, pp.571-596, 2007.
DOI : 10.1016/j.geomphys.2006.05.003

M. J. Pflaum, Analytic and Geometric Study of Stratified Spaces, Lecture Notes in Mathematics, vol.510, 2001.

T. Ratiu and R. Schmid, The differentiable structure of three remarkable diffeomorphism groups, Mathematische Zeitschrift, vol.10, issue.1, pp.81-100, 1981.
DOI : 10.1007/BF01214340

S. Sasaki, On differentiable manifolds with certain structures which are closely related to almost contact structure, I, Tohoku Mathematical Journal, vol.12, issue.3, pp.459-476, 1960.
DOI : 10.2748/tmj/1178244407

S. Sasaki, Contact structures on Brieskorn manifolds (lecture Japan Mathematical Society, Shiego Sasaki Selected Papers, pp.349-363, 1975.

J. Serre, Lie Algebras and Lie Groups, 1965.

J. Souriau, Structure des Systèmes Dynamiques, Dunod. Paris. English translation by, Tuynman as Structure of Dynamical Systems. A Symplectic View of Physics, 1997.

P. Stefan, Accessible Sets, Orbits, and Foliations with Singularities, Proc. Lond, pp.699-713, 1974.
DOI : 10.1112/plms/s3-29.4.699
URL : http://plms.oxfordjournals.org/cgi/content/short/s3-29/4/699

H. Sussmann, Orbits of families of vector fields and integrability of distributions, Transactions of the American Mathematical Society, vol.180, pp.171-188, 1973.
DOI : 10.1090/S0002-9947-1973-0321133-2

J. Ortega and T. R. Ratiu, Momentum Maps and Hamiltonian Reduction, Progress in Mathematics, vol.222, 2004.
DOI : 10.1007/978-1-4757-3811-7

C. Willett, Contact reduction, Transactions of the American Mathematical Society, vol.354, issue.10, pp.4245-4260, 2002.
DOI : 10.1090/S0002-9947-02-03045-3

M. Zambon and C. Zhu, Contact reduction and groupoid actions, Transactions of the American Mathematical Society, vol.358, issue.03, pp.1365-1401, 2006.
DOI : 10.1090/S0002-9947-05-03832-8

N. T. Zung, Proper groupoids and momentum maps: Linearization, affinity, and convexity, Annales Scientifiques de l?????cole Normale Sup??rieure, vol.39, issue.5, pp.39-841, 2006.
DOI : 10.1016/j.ansens.2006.09.002

P. Xu, Momentum Maps and Morita Equivalence, Journal of Differential Geometry, vol.67, issue.2, pp.289-333, 2004.
DOI : 10.4310/jdg/1102536203

P. Xu, Morita Equivalent Symplectic Groupoids, Math. Sci. Res. Inst. Publ, vol.20, pp.291-311, 1989.
DOI : 10.1007/978-1-4613-9719-9_20

A. Weinstein, LINEARIZATION OF REGULAR PROPER GROUPOIDS, Journal of the Institute of Mathematics of Jussieu, vol.1, issue.03, pp.493-511, 2002.
DOI : 10.1017/S1474748002000130

A. Weinstein, Linearization Problems for Lie Algebroids and Lie Groupoids, [1800493]. Conférence MOshé Flato, Math. Phys. Stud, vol.22, pp.333-341, 1999.