@article{YNDUR_IN_1972,
title={Rigorous Constraints,
Bounds,
and Relations for Scattering Amplitudes},
volume={44},
ISSN={0034-6861},
url={http://dx.doi.org/10.1103/revmodphys.44.645},
DOI={10.1103/revmodphys.44.645},
number={4},
journal={Reviews of Modern Physics},
publisher={American Physical Society (APS)},
author={YNDURÁIN,
F. J.},
year={1972},
month=oct,
pages={645–667} }