@ARTICLE {2607,
author={C. Sernadas and J. Rasga and W. Carnielli },
doi={},
journal={Journal of Symbolic Logic},
title={Modulated fibring and the collapsing problem},
year={2002},
month={January},
volume={67},
number={4},
pages={1541-1569},
ISSN={0022-4812}
}