@article{ref1,
title="Rigidity, stability, and motion in perceptual space : A discussion of some mathematical principles operative in the perception of relative motion and of their possible function as determinants of a static perceptual space",
journal="Acta psychologica",
year="1958",
author="Johansson, G.",
volume="14",
number="",
pages="359-370",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0001-6918",
doi="",
url="http://dx.doi.org/"
}