Access to digital finance : equity crowdfunding across countries and platforms / Saul Estrin (London School of Economics and IZA), Susanna Khavul (San José State University and London School of Economics), Alexander S. Kritikos (DIW Berlin, University of Potsdam, IAB and IZA), Jonas Löher (Institut für Mittelstandsforschung (IfM)) ; IZA Institute of Labor Economics