@article{ref1,
title="Methodologic problems in matched-pair studies using twins",
journal="Progress in clinical and biological research",
year="1981",
author="Hrubec, Z.",
volume="69",
number="C",
pages="1-7",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0361-7742",
doi="",
url="http://dx.doi.org/"
}