Talk given for the Conference for the foundation of the Institut de Physique Théorique Philippe Meyer (February 2012) Open questions in Condensed Matter
Talk given for the Les Houches workshop on ``Material deformations'' (January 2012) Disordered Elastic systems
INSTANS Summer School on ``Interdisciplinary Statistical and Field Theory Approaches to Nanophysics and low-dimensional Systems'' (Oxford - August 2007) : Low dimensional strongly correlated systems