1. RWI – Leibniz Institute for Economic Research, Essen, Düsseldorf Institute for Competition Economics (DICE), Heinrich‐Heine‐Universität Düsseldorf, and Institute for the Study of Labor (IZA)
2. RWI – Leibniz Institute for Economic Research, Essen, and Ruhr‐Universität Bochum (RUB)