@article{Olsen1997,
author = {Olsen, J. and Schmidt, M.M. and Christensen, K.},
title= {Evaluation of nature-nurture impact on reproductive health using half-siblings},
year = {1997},
doi = {10.1097/00001648-199701000-00001},
journal = {Epidemiology},
volume = {8},
number = {1},
pages = {6--11},
}