Walter, W. “Einführung: Fertilität - Kinderwunsch Und Realität: Zur Aktualität Des Bevölkerungsthemas: Introduction to Thematic Block I: ‘Fertility: Desire for Children and Real outcomes’: Is Birth Decline a New Issue?”. Journal of Family Research, vol. 17, no. 1, Mar. 2020, pp. p. 4-7, https://ubp.uni-bamberg.de/jfr/index.php/jfr/article/view/376.