@InCollection{ BeckertHaehnleManyaLD99,
author = {Bernhard Beckert and Reiner H\"ahnle and Felip
Manya},
title = {The SAT Problem of Signed CNF Formulas},
booktitle = {Labelled Deduction},
editor = {M. D'Agostino and D. Basin and D. Gabbay and
S. Matthews and L. Vigano},
pages = {59--80},
publisher = {Kluwer, Dordrecht},
year = {2000}
}
