Open Power System Data - Frictionless data for electricity system modelling. - Wiese, Frauke; Schlecht, Ingmar; Bunke, Wolf-Dieter; Gerbaulet, Clemens; Hirth, Lion; Jahn, Martin; Kunz, Friedrich; Lorenz, Casimir; Mühlenpfordt, Jonathan; Reimann, Juliane; Schill, Wolf-Peter (CoRR, 2018)