Freise, D., Schmitz, H., &; Westphal, M. (2022). Late-Career Unemployment and Cognitive Abilities. Journal of Health Economics, 86.https://doi.org/10.1016/j.jhealeco.2022.102689 

Westphal, M., Kamhöfer, D. A., &; Schmitz, H. (2022). Marginal College Wage Premium under Selection into Employment. Economic Journal, 132(646), 2231–2272.https://doi.org/10.1093/ej/ueac021 

Schmitz, H., &; Westphal, M. (2021). The dynamic and heterogeneous effects of retirement on cognitive decline (Vol. 918). RWI - Leibniz-Institut für Wirtschaftsforschung, Ruhr-University Bochum, TU Dortmund University, University of Duisburg-Essen.

Kamhöfer, D. A., Schmitz, H., &; Westphal, M. (2019). Heterogeneity in Marginal Non-Monetary Returns to Higher Education. Journal of the European Economic Association, 17(1), 205–244.https://doi.org/10.1093/jeea/jvx058 

Schmitz, H., &; Westphal, M. (2017). Informal Care and Long-term Labor Market Outcomes. Journal of Health Economics, 56, 1–18.https://doi.org/10.1016/j.jhealeco.2017.09.002 

Schmitz, H., &; Westphal, M. (2015). Short-and medium-term effects of informal care provision on female caregivers’ health. Journal of Health Economics, 42, 174–185.https://doi.org/10.1016/j.jhealeco.2015.03.002