C. C. Dahn, H. C. Harris, and F. J. Vrba, Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs, The Astronomical Journal, vol.124, issue.2, p.1170, 2002.
DOI : 10.1086/341646

P. T. De-zeeuw, R. Hoogerwerf, J. H. De-bruijne, A. G. Brown, and A. Blaauw, A [ITAL]Hipparcos[/ITAL] Census of the Nearby OB Associations, The Astronomical Journal, vol.117, issue.1, p.354, 1999.
DOI : 10.1086/300682

T. A. Fleming, M. S. Giampapa, and D. Garza, The Quiescent Corona of VB 10, The Astrophysical Journal, vol.594, issue.2, p.982, 2003.
DOI : 10.1086/376968

T. A. Fleming, M. S. Giampapa, and J. H. Schmitt, An X???Ray Flare Detected on the M8 Dwarf VB 10, The Astrophysical Journal, vol.533, issue.1, p.372, 2000.
DOI : 10.1086/308657

R. Jayawardhana, S. Mohanty, G. Basri, R. Jayawardhana, S. Mohanty et al., Probing Disk Accretion in Young Brown Dwarfs, The Astrophysical Journal, vol.578, issue.2, pp.141-282, 2002.
DOI : 10.1086/344707

S. K. Leggett, D. A. Golimowski, and X. Fan, Infrared Photometry of Late???M, L, and T Dwarfs, The Astrophysical Journal, vol.564, issue.1, p.452, 2002.
DOI : 10.1086/324037

N. Loiseau, XMM-Newton Science Analysis System Users' Guide, 2003.

T. Montmerle, N. Grosso, Y. Tsuboi, and K. Koyama, Rotation and X???Ray Emission from Protostars, The Astrophysical Journal, vol.532, issue.2, p.1097, 2000.
DOI : 10.1086/308611

F. Ochsenbein, P. Bauer, and J. Marcout, The VizieR database of astronomical catalogues, Astronomy and Astrophysics Supplement Series, vol.143, issue.1, p.23, 2000.
DOI : 10.1051/aas:2000169

T. Preibisch and H. Zinnecker, X-Ray Properties of the Young Stellar and Substellar Objects in the IC 348 Cluster: The [ITAL]Chandra[/ITAL] View, The Astronomical Journal, vol.123, issue.3, p.1613, 2002.
DOI : 10.1086/338851

R. E. Rutledge, G. Basri, E. L. Martín, L. Bildsten, J. H. Schmitt et al., [ITAL]Chandra[/ITAL] Detection of an X-Ray Flare from the Brown Dwarf LP 944-20, Brown Dwarfs, Proceedings of IAU Symposium, pp.141-150, 2000.
DOI : 10.1086/312817

Y. Tsuboi, Y. Maeda, and E. D. Feigelson, Coronal X-Ray Emission from an Intermediate-Age Brown Dwarf, The Astrophysical Journal, vol.587, issue.1, p.51, 2003.
DOI : 10.1086/375017

S. J. Wolk, at University of Hawai'i, Honolulu, Hawai'i. Edited by Eduardo Martín., 447?+ XMM-Newton Survey Science Centre The First XMM-Newton Serendipitous Source Catalogue, Proceedings of IAU Symposium 211 Fundamental Properties of Binary Ultracool Dwarfs, 2001.

E. S. Workshop, Science with Adaptive Optics, Member of the Local Organizing Committee 194 TRAINING COURSE & SCHOOLS, pp.16-19

. Dec, Extrasolar Planets and Brown Dwarfs, First Advanced Chilean School in Astrophysics, 2003.

. Sept, Observing Summer School, Asiago Observatory (Network of European Observatories in the North), sponsored by the European Community 15, 2001.

. Institute-for-astronomy, A. Hawai-'iwfpc2, and S. ). Windows, working on brown dwarfs and halo-binaries, using XMM-and IR-data, observing with UH88 " on Mauna Kea Observatory OBSERVATIONAL EXPERIENCE High Angular Resolution Hubble Space Telescope Intensive use of HST high resolution cameras Development of a PSF fitting program to analyse binary stars images, with a calibrated accuracy of 0.001 " on the relative astrometry. High Angular Resolution Adaptive Optics at the ESO/VLT. Intensive use of VLT/NACO (P.I on 3 programs). Participation to the commissioning of the instrument in Paranal Spectroscopy Low Resolution Spectroscopy. Observation and Analysis of VLT/FORS2 and HST/STIS low resolution spectra X-Ray XMM-Newton. Experienced with the processing and analysis of XMM X-Ray data, Adobe Illustrator & Photoshop Languages French Mother tongue

Y. Studentship, E. S. O-headquarters-in-garching-bouy, H. Martín, E. L. Brandner, and W. , Germany 2001 5 Months Undergraduate Studentship at the IfA in Honolulu, U.S.A REFEREED PUBLICATIONS 2004 Discovery of a triple system of brown dwarfs with the Hubble Space Telescope, prep. for Astrophysical Journal, 2004.

W. Brandner, E. L. Martín, and . Bouy, accepted for publication in Astronomy & Astrophysics First determination of the orbit and dynamical mass of a binary L1 dwarf Bouy 341 A young binary Brown Dwarf in the R-CrA star formation region The Astronomical Journal, Multiplicity of Nearby Free Floating Ultracool Dwarfs : a HST/WFPC2 search for companions, pp.1526-1554, 2003.

N. Refereed, H. And-proceedings, W. Bouy, E. L. Brandner, and . Martín, Statistical and Physical properties of binaries of low-mass stars and brown dwarfs SF2A-2004 : Semaine de l'Astrophysique Francaise, 2003.

W. Brandner and &. H. Bouy, Substellar companions to Brown Dwarfs : First steps toward a direct detection of Exoplanets, Towards Other Earths -Darwin/TPF and the Search for Extrasolar Terrestrial Planets, 2003.

E. L. Martín, M. Connelley, D. Potter, H. Bouy, R. E. Iau-symposium et al., Norris High Resolution Observations of Binary Brown Dwarfs, Hervé Bouy & Wolfgang Brandner Science with Adaptive Optics NAOS+CONICA at YEPUN : first VLT adaptive optics system sees first light, Brown Dwarfs Companions to Solar-type Stars and other Brown dwarfs Brandner HST Observations of Candidates and Bona-fide Binary Brown Dwarfs, Bouy et al, pp.241-245, 2002.

H. A. Abt, R. C. Barnes, E. S. Biggs, and P. S. Osmer, The Frequency of Spectroscopic Binaries in the Pleiades., The Astrophysical Journal, vol.142, p.1604, 1965.
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C. Alard, Image subtraction using a space-varying kernel, Astronomy and Astrophysics Supplement Series, vol.144, issue.2, p.363, 2000.
DOI : 10.1051/aas:2000214

F. Allard, P. H. Hauschildt, D. R. Alexander, A. Tamanai, and A. Schweitzer, The Limiting Effects of Dust in Brown Dwarf Model Atmospheres, The Astrophysical Journal, vol.556, issue.1, p.357, 2001.
DOI : 10.1086/321547

F. Allard, P. H. Hauschildt, and A. Schweitzer, Spherically Symmetric Model Atmospheres for Low???Mass Pre???Main???Sequence Stars with Effective Temperatures between 2000 and 6800 K, The Astrophysical Journal, vol.539, issue.1, p.366, 2000.
DOI : 10.1086/309218

P. Andre and T. Montmerle, From T Tauri stars to protostars: Circumstellar material and young stellar objects in the rho Ophiuchi cloud, The Astrophysical Journal, vol.420, p.837, 1994.
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C. A. Bailer-jones, Spectroscopic rotation velocities of??L??dwarfs from VLT/UVES and their comparison with periods from photometric monitoring, Astronomy & Astrophysics, vol.419, issue.2, p.703, 2004.
DOI : 10.1051/0004-6361:20040965

C. A. Bailer-jones and R. Mundt, Variability in ultra cool dwarfs: Evidence for the evolution of surface features, Astronomy and Astrophysics, vol.367, issue.1, p.218, 2001.
DOI : 10.1051/0004-6361:20000416

I. Baraffe, G. Chabrier, F. Allard, and P. H. Hauschildt, Evolutionary models for low-mass stars and brown dwarfs: Uncertainties and limits at very young ages, Astronomy and Astrophysics, vol.382, issue.2, p.563, 2002.
DOI : 10.1051/0004-6361:20011638

URL : https://hal.archives-ouvertes.fr/hal-00008484

G. Basri, G. W. Marcy, and J. R. Graham, Lithium in Brown Dwarf Candidates: The Mass and Age of the Faintest Pleiades Stars, The Astrophysical Journal, vol.458, p.600, 1996.
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G. Basri and E. L. Martín, PP[CLC]l[/CLC] 15: The First Brown Dwarf Spectroscopic Binary, The Astronomical Journal, vol.118, issue.5, p.2460, 1999.
DOI : 10.1086/301079

J. Bibliography-biretta, J. Stsci-blommaert, R. Siebenmorgen, and A. Coulais, ISO Handbook, Volume III Bodenheimer, e. a. 1999, Space Science Series, ASP Conf. Ser. 134: Brown Dwarfs and Extrasolar Planets, pp.115-121, 1997.

A. P. Boss, Gas Giant Protoplanet Formation: Disk Instability Models with Thermodynamics and Radiative Transfer, The Astrophysical Journal, vol.563, issue.1, p.367, 2001.
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J. Bouvier, G. Duchêne, J. Mermilliod, and T. Simon, The formation and evolution of binary systems, Astronomy & Astrophysics, vol.375, issue.3, p.989, 2001.
DOI : 10.1051/0004-6361:20010915

URL : https://hal.archives-ouvertes.fr/hal-00012160

H. Bouy, W. Brandner, and E. L. Martín, WFPC2 Search for Companions, The Astronomical Journal, vol.126, issue.3, p.1526, 2003.
DOI : 10.1086/377343

A. J. Burgasser, J. D. Kirkpatrick, and M. E. Brown, The Spectra of T Dwarfs. I. Near???Infrared Data and Spectral Classification, The Astrophysical Journal, vol.564, issue.1, p.421, 2002.
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A. J. Burgasser, J. D. Kirkpatrick, and M. E. Brown, Discovery of Four Field Methane (T-Type) Dwarfs with the Two Micron All-Sky Survey, The Astrophysical Journal, vol.522, issue.1, pp.65-512, 1999.
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A. Burrows and C. M. Sharp, Chemical Equilibrium Abundances in Brown Dwarf and Extrasolar Giant Planet Atmospheres, The Astrophysical Journal, vol.512, issue.2, p.843, 1999.
DOI : 10.1086/306811

B. W. Casey, R. D. Mathieu, L. P. Vaz, J. Andersen, and N. B. Suntzeff, The Pre???Main-Sequence Eclipsing Binary TY Coronae Australis: Precise Stellar Dimensions and Tests of Evolutionary Models, The Astronomical Journal, vol.115, issue.4, p.1617, 1998.
DOI : 10.1086/300270

G. Chabrier, I. Baraffe, F. Allard, and P. Hauschildt, Evolutionary Models for Very Low???Mass Stars and Brown Dwarfs with Dusty Atmospheres, The Astrophysical Journal, vol.542, issue.1, p.464, 2000.
DOI : 10.1086/309513

URL : https://hal.archives-ouvertes.fr/hal-00014527

L. M. Close, D. Potter, and W. Brandner, Discovery of a 0.??15 Binary Brown Dwarf, 2MASS J1426316+155701, with Gemini/Hokupa???a Adaptive Optics, The Astrophysical Journal, vol.566, issue.2, p.1095, 2002.
DOI : 10.1086/337916

L. M. Close, N. Siegler, M. Freed, and B. Biller, Detection of Nine M8.0???L0.5 Binaries: The Very Low Mass Binary Population and Its Implications for Brown Dwarf and Very Low Mass Star Formation, The Astrophysical Journal, vol.587, issue.1, p.407, 2003.
DOI : 10.1086/368177

L. M. Close, N. Siegler, D. Potter, W. Brandner, and J. Liebert, An Adaptive Optics Survey of M8-M9 Stars: Discovery of Four Very Low Mass Binaries with at Least One System Containing a Brown Dwarf Companion, The Astrophysical Journal, vol.567, issue.1, p.53, 2002.
DOI : 10.1086/339795

R. M. Cutri, M. F. Skrutskie, and S. Van-dyk, VizieR Online Data Catalog, 2003.

C. C. Dahn, H. C. Harris, and F. J. Vrba, Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs, The Astronomical Journal, vol.124, issue.2, p.1170, 2002.
DOI : 10.1086/341646

P. T. De-zeeuw, R. Hoogerwerf, J. H. De-bruijne, A. G. Brown, and A. Blaauw, A [ITAL]Hipparcos[/ITAL] Census of the Nearby OB Associations, The Astronomical Journal, vol.117, issue.1, p.354, 1999.
DOI : 10.1086/300682

X. Delfosse, C. G. Tinney, and T. Forveille, Searching for very low-mass stars and brown dwarfs with DENIS, Astronomy and Astrophysics Supplement Series, vol.135, issue.1, p.41, 1999.
DOI : 10.1051/aas:1999158

E. J. Delgado-donate, C. J. Clarke, and . Bate, = 5, Monthly Notices of the Royal Astronomical Society, vol.342, issue.3, p.926, 2003.
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R. H. Durisen, M. F. Sterzik, and B. K. Pickett, A two-step initial mass function:, Astronomy and Astrophysics, vol.371, issue.3, p.952, 2001.
DOI : 10.1051/0004-6361:20010390

M. L. Enoch, M. E. Brown, and A. J. Burgasser, Photometric Variability at the L/T Dwarf Boundary, The Astronomical Journal, vol.126, issue.2, p.1006, 2003.
DOI : 10.1086/376598

N. Epchtein, B. De-batz, and L. Capoani, The Messenger, p.27, 1997.

M. Fernández and F. Comerón, Intense accretion and mass loss of a very low mass young stellar object, Astronomy & Astrophysics, vol.380, issue.1, p.264, 2001.
DOI : 10.1051/0004-6361:20011443

L. Festin, Spectroscopy of new Pleiades brown dwarfs, Monthly Notices of the Royal Astronomical Society, vol.298, issue.2, p.34, 1998.
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D. A. Fischer and G. W. Marcy, Multiplicity among M dwarfs, The Astrophysical Journal, vol.396, p.178, 1992.
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T. A. Fleming, M. S. Giampapa, and D. Garza, The Quiescent Corona of VB 10, The Astrophysical Journal, vol.594, issue.2, p.982, 2003.
DOI : 10.1086/376968

T. A. Fleming, M. S. Giampapa, and J. H. Schmitt, An X???Ray Flare Detected on the M8 Dwarf VB 10, The Astrophysical Journal, vol.533, issue.1, p.372, 2000.
DOI : 10.1086/308657

M. Freed, L. M. Close, and N. Siegler, Discovery of a Tight Brown Dwarf Companion to the Low???Mass Star LHS 2397a, The Astrophysical Journal, vol.584, issue.1, p.453, 2003.
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E. J. Gaidos, G. W. Henry, and S. M. Henry, Spectroscopy and Photometry of Nearby Young Solar Analogs, The Astronomical Journal, vol.120, issue.2, p.1006, 2000.
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T. R. Geballe, G. R. Knapp, and S. K. Leggett, Toward Spectral Classification of L and T Dwarfs: Infrared and Optical Spectroscopy and Analysis, The Astrophysical Journal, vol.564, issue.1, p.466, 2002.
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C. R. Gelino, M. S. Marley, J. A. Holtzman, A. S. Ackerman, and K. Lodders, ???Band Observations, The Astrophysical Journal, vol.577, issue.1, p.433, 2002.
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J. E. Gizis, D. G. Monet, and I. N. Reid, New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence, The Astronomical Journal, vol.120, issue.2, p.1085, 2000.
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J. E. Gizis, I. N. Reid, and G. R. Knapp, Observations of Binary Very Low Mass Stars and Brown Dwarfs, The Astronomical Journal, vol.125, issue.6, p.3302, 2003.
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D. A. Golimowski, C. J. Burrows, S. R. Kulkarni, B. R. Oppenheimer, and R. A. Brukardt, Wide Field Planetary Camera 2 Observations of the Brown Dwarf Gliese 229B: Optical Colors and Orbital Motion, The Astronomical Journal, vol.115, issue.6, p.2579, 1998.
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N. I. Gorlova, M. R. Meyer, G. H. Rieke, and J. Liebert, Gravity Indicators in the Near???Infrared Spectra of Brown Dwarfs, The Astrophysical Journal, vol.593, issue.2, p.1074, 2003.
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M. Goto, N. Kobayashi, and H. Terada, Near-Infrared Adaptive Optics Spectroscopy of Binary Brown Dwarfs HD 130948B and HD 130948C, The Astrophysical Journal, vol.567, issue.1, p.59, 2002.
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M. F. Graham, J. Meaburn, and S. T. Garrington, MERLIN Radio Detection of an Interaction Zone within a Binary Orion Proplyd System, The Astrophysical Journal, vol.570, issue.1, p.222, 2002.
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E. W. Guenther and G. Wuchterl, Companions of old brown dwarfs, and very low mass stars, Astronomy and Astrophysics, vol.401, issue.2, p.677, 2003.
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J. L. Halbwachs, M. Mayor, S. Udry, and F. Arenou, Multiplicity among solar???type stars, Astronomy & Astrophysics, vol.397, issue.1, p.159, 2003.
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N. C. Hambly, S. T. Hodgkin, M. R. Cossburn, and R. F. Jameson, Brown dwarfs in the Pleiades and the initial mass function across the stellar/substellar boundary, Monthly Notices of the Royal Astronomical Society, vol.303, issue.4, p.835, 1999.
DOI : 10.1046/j.1365-8711.1999.02283.x

R. S. Harrington, Dynamical evolution of triple stars., The Astronomical Journal, vol.73, p.190, 1968.
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P. H. Hauschildt, F. Allard, and E. Baron, The NextGen Model Atmosphere Grid for \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $3000\leq T_{\mathrm{eff}\,}\leq \mathrm{10,000}\,$ \end{document} K, The Astrophysical Journal, vol.512, issue.1, p.377, 1999.
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S. L. Hawley, K. R. Covey, and G. R. Knapp, Characterization of M, L, and T Dwarfs in the Sloan Digital Sky Survey, The Astronomical Journal, vol.123, issue.6, p.3409, 2002.
DOI : 10.1086/340697

R. Jayawardhana, D. R. Ardila, B. Stelzer, and K. E. Haisch, A Disk Census for Young Brown Dwarfs, The Astronomical Journal, vol.126, issue.3, p.1515, 2003.
DOI : 10.1086/377144

R. Jayawardhana, S. Mohanty, and G. Basri, Probing Disk Accretion in Young Brown Dwarfs, The Astrophysical Journal, vol.578, issue.2, p.141, 2002.
DOI : 10.1086/344707

R. Jayawardhana, S. Mohanty, and G. Basri, Evidence for a T Tauri Phase in Young Brown Dwarfs, The Astrophysical Journal, vol.592, issue.1, p.282, 2003.
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V. Joergens, M. Fernández, J. M. Carpenter, and R. Neuhäuser, Rotational Periods of Very Young Brown Dwarfs and Very Low Mass Stars in Chamaeleon I, The Astrophysical Journal, vol.594, issue.2, p.971, 2003.
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M. Kenworthy, K. Hofmann, and L. Close, Gliese 569B: A Young Multiple Brown Dwarf System?, The Astrophysical Journal, vol.554, issue.1, p.67, 2001.
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J. Kepler, Astronomia nova, 1609.

J. Kepler, Harmonices mvndi libri (Lincii Austriae, sumptibus G. Tampachii, excudebat I. Plancvs, 1619.

J. D. Kirkpatrick, C. C. Dahn, and D. G. Monet, Brown Dwarf Companions to G-Type Stars. I. Gliese 417B and Gliese 584C, The Astronomical Journal, vol.121, issue.6, p.3235, 2001.
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J. D. Kirkpatrick, I. N. Reid, and J. Liebert, Dwarfs Cooler than ???M???: The Definition of Spectral Type ???L??? Using Discoveries from the 2 Micron All???Sky Survey (2MASS), The Astrophysical Journal, vol.519, issue.2, p.802, 1999.
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J. D. Kirkpatrick, I. N. Reid, and J. Liebert, 67 Additional L Dwarfs Discovered by the Two Micron All Sky Survey, The Astronomical Journal, vol.120, issue.1, p.447, 2000.
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B. F. Lane, Z. Osorio, M. R. Britton, M. C. Martín, E. L. Kulkarni et al., The Orbit of the Brown Dwarf Binary Gliese 569B, The Astrophysical Journal, vol.560, issue.1, p.390, 2001.
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S. K. Leggett, Infrared colors of low-mass stars, The Astrophysical Journal Supplement Series, vol.82, p.351, 1992.
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S. K. Leggett, F. Allard, T. R. Geballe, P. H. Hauschildt, and A. Schweitzer, Infrared Spectra and Spectral Energy Distributions of Late M and L Dwarfs, The Astrophysical Journal, vol.548, issue.2, p.908, 2001.
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S. K. Leggett, D. A. Golimowski, and X. Fan, Infrared Photometry of Late???M, L, and T Dwarfs, The Astrophysical Journal, vol.564, issue.1, p.452, 2002.
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R. Lenzen, M. Hartung, and W. Brandner, in Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, Proceedings of the SPIE, pp.944-952, 2003.

M. C. Liu, J. Najita, and A. T. Tokunaga, A Survey for Circumstellar Disks around Young Substellar Objects, The Astrophysical Journal, vol.585, issue.1, p.372, 2003.
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N. Loiseau, XMM-Newton Science Analysis System Users' Guide, 2003.

M. Lombardi and J. Alves, Mapping the interstellar dust with near-infrared observations: An optimized multi-band technique, Astronomy and Astrophysics, vol.377, issue.3, p.1023, 2001.
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K. L. Luhman and G. H. Rieke, Low???Mass Star Formation and the Initial Mass Function in the ?? Ophiuchi Cloud Core, The Astrophysical Journal, vol.525, issue.1, p.440, 1999.
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E. L. Martín, R. Rebolo, and M. R. Zapatero-osorio, Spectroscopy of New Substellar Candidates in the Pleiades: Toward a Spectral Sequence for Young Brown Dwarfs, The Astrophysical Journal, vol.469, p.706, 1996.
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E. L. Martín, D. Barrado-y-navascués, I. Baraffe, H. Bouy, and S. Dahm, Wide Field Planetary Camera 2 Survey for Brown Dwarf Binaries in the ?? Persei and Pleiades Open Clusters, The Astrophysical Journal, vol.594, issue.1, p.525, 2003.
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E. L. Martín, G. Basri, and W. Brandner, Discovery of a Very Low Mass Binary with the [ITAL]Hubble Space Telescope[/ITAL]Near-Infrared Camera and Multiobject Spectrometer, The Astrophysical Journal, vol.509, issue.2, p.113, 1998.
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E. L. Martín, W. Brandner, and J. Bouvier, Membership and Multiplicity among Very Low Mass Stars and Brown Dwarfs in the Pleiades Cluster, The Astrophysical Journal, vol.543, issue.1, p.299, 2000.
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E. L. Martín, X. Delfosse, and G. Basri, Spectroscopic Classification of Late-M and L Field Dwarfs, The Astronomical Journal, vol.118, issue.5, p.2466, 1999.
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E. L. Martín, X. Delfosse, and S. Guieu, Spectroscopic Identification of DENIS-selected Brown Dwarf Candidates in the Upper Scorpius OB Association, The Astronomical Journal, vol.127, issue.1, p.449, 2004.
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