R. Ortmann and E. Pummerer, “Distortional effects of separate accounting and formula apportionment on factor allocation,”10.1007/s11573-022-01133-5__Journal of Business Economics, 2023, doi:10.1007/s11573-022-01133-5 .

R. Ortmann and D. Schindler, Income Shifting and Management Incentives. 2022.

S. Warkulat, S. Krull, R. Ortmann, N. Klocke, and M. Pelster, “COVID-19 reporting and willingness to pay for leisure activities,” Covid Economics, no. 83, pp. 183–205, 2021.

R. Ortmann, S. Warkulat, S. Krull, N. Klocke, and M. Pelster, COVID-19 Reporting and Willingness to Pay for Leisure Activities, vol. 83. 2021.

R. Ortmann, D. Simons, and D. Voeller, Real effects of an international tax reform for MNEs, vol. 64. 2021.

R. Ortmann, M. Pelster, and S. T. Wengerek, “COVID-19 and investor behavior,” Finance Research Letters, vol. 37, 2020.

R. Ortmann, M. Pelster, and S. T. Wengerek, “COVID-19 and investor behavior,”10.1016/j.frl.2020.101717__Finance Research Letters, vol. 37, Art. no. 101717, 2020, doi:10.1016/j.frl.2020.101717 .

R. Ortmann and C. Sureth-Sloane, “Can the CCCTB Alleviate Tax Discrimination against Loss-Making European Multinational Groups?,” Journal of Business Economics, vol. 86, no. 5, pp. 441–475, 2016.

R. Ortmann and C. Sureth-Sloane, “Can the CCCTB Alleviate Tax Discrimination against Loss-Making European Multinational Groups?,”10.1007/s1007-015-0780-6__Journal of Business Economics, vol. 86, no. 5, pp. 441–475, 2016, doi:10.1007/s1007-015-0780-6 .

R. Ortmann, Uncertainty in Weighting Formulary Apportionment Factors. How Does Weighting Uncertainty Impact After-Tax Income of Multinational Groups?, vol. 2015–10. 2015.

R. Ortmann, Uncertainty in Weighting Formulary Apportionment Factors and Its Impact on After-Tax Income of Multinational Groups, vol. 198. 2015.

R. Ortmann, “Uncertainty in Weighting Formulary Apportionment Factors,” Die Betriebswirtschaft, vol. 75, no. 3, pp. 161–177, 2015.

R. Ortmann and C. Sureth-Sloane, Can the CCCTB Alleviate Tax Discrimination against Loss-Making European Multinational Groups?, vol. 165. 2014.