Discrete least squares polynomial approximation with random evaluations − application to parametric and stochastic elliptic PDEsAbdellah Chkifa, Albert Cohen, Giovanni Migliorati, Fabio Nobile and Raul TemponeESAIM: M2AN, 49 3 (2015) 815-837DOI: https://doi.org/10.1051/m2an/2014050