Spengel, Christoph, Jost Henrich Heckemeyer, Hannah Nusser, Oliver Klar und Frank Streif (2016), The Impact of Tax Planning on Forward-Looking Effective Tax Rates, Taxation Paper Series, European Commission .

Spengel, Christoph, Jost Henrich Heckemeyer, Rainer Bräutigam, Katharina Nicolay, Oliver Klar und Kathrin Stutzenberger (2016), The Effects of Tax Reforms to Address the Debt-Equity Bias on the Cost of Capital and on Effective Tax Rates, European Commission Taxation Papers , Brüssel.

Spengel, Christoph, Frank Schmidt, Jost Henrich Heckemeyer, Katharina Nicolay, Alexandra Bartholmeß, Rainer Bräutigam, Julia Braun, Verena Dutt, Maria Theresia Evers, Christoph Harendt, Oliver Klar, Hannah Nusser, Marcel Olbert, Olena Pfeiffer, Daniela Steinbrenner, Frank Streif und Maximilian Todtenhaupt (2017), Effective Tax Levels Using the Devereux/Griffith Methodology: Final Report 2016, Project for the EU Commission TAXUD/2013/CC/120 Final Report 2016, Mannheim

Spengel, Christoph, Jost Henrich Heckemeyer, Hannah Nusser, Oliver Klar und Frank Streif (2016), The Impact of Tax Planning on Forward-Looking Effective Tax Rates, EU-Kommission, Mannheim

Spengel, Christoph, Jost Henrich Heckemeyer, Rainer Bräutigam, Katharina Nicolay, Oliver Klar und Kathrin Stutzenberger (2016), The Effects of Tax Reforms to Address the Debt-Equity Bias on the Cost of Capital and on Effective Tax Rates, Europäische Kommission, Mannheim