John E. Knodel. Demographic behavior in the past. A study of fourteen German village populations in the eighteenth and nineteenth centuries . Inverse and Back Projection Inverse and back projection take a different approach to the parish register era. Inverse projection works forward in time between two age-distributions, which may be centuries apart.
Back projection works backward in time from an age distribution at the end of the period of study.
Generalized inverse projection. Population Studies , Vol. 47, No. 2, Jul 1993. Patrick R. Galloway. A reconstruction of the population of north Italy from 1650 to 1881 using annual inverse projection with comparisons to England, France, and Sweden.