@article{ref1,
title="Foreword to "The occurrence of revolutions"",
journal="Journal of abnormal psychology (1906)",
year="1918",
author="Sidis, B.",
volume="13",
number="4",
pages="215-216",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0145-2339",
doi="10.1037/h0070899",
url="http://dx.doi.org/10.1037/h0070899"
}