Werke:
- Kirchenmitglieder und Kirchensteueraufkommen in Deutschland : sieben Essays zur langfristigen Projektion bis 2060
- German Churches in Times of Demographic Change and Declining Affiliation: A Projection to 2060
- German Churches in Times of Demographic Change and Declining Affiliation: A Projection to 2060
- Does church tax matter? The influence of church tax on leaving the church