Worries across time and age in Germany : bringing together open- and close-ended questions / Julia M. Rohrer (DIW Berlin, FUB and University of Leipzig), Martin Bruemmer (Independent Researcher, Leipzig), Juergen Schupp (DIW Berlin, FUB and IZA), Gert G. Wagner (DIW Berlin, IZA, MPIB and TUB) ; IZA Institute of Labor Economics. Bonn, Germany : IZA Institute of Labor Economics, June 2017