@article{Wilson1988,
author = {Wilson, C. and Oeppen, J. and Pardoe, M.},
title= {What Is Natural Fertility? The Modelling of a Concept},
year = {1988},
doi = {10.2307/3644106},
journal = {Population Index},
volume = {54},
number = {1},
pages = {4--20},
}