@INPROCEEDINGS {5812,
author={C. Sernadas and M.P.G. Gouveia and M. A. Lopes},
doi={},
booktitle={Foundations of Models and Languages for Data and Objects},
title={Gentzen-type system for verification in conceptual modeling},
year={1991},
month={September},
volume={-},
pages={215-228} 
}