An economic analysis of the optimal design of targeted taxes, cash, and in-kind benefits for single women in Germany, conditional on the presence and age of children, with additional analyses of the relationship between the optimal design and changes to in-kind benefits for child care, conditional on employment, based on data from 5,801 18- through 60-year-old women for the fiscal years 1999-2004, who were not self-employed, retired, or in full-time education, from the German Socio-Economic Panel (SOEP)