@article{DBLP:journals/fuin/Szalas96,
author = {Andrzej Szalas},
title = {On Natural Deduction in First-Ortder Fixpoint Logics},
journal = {Fundam. Inform.},
volume = {26},
number = {1},
year = {1996},
pages = {81-94},
ee = {http://dx.doi.org/10.3233/FI-1996-2616},
bibsource = {DBLP, http://dblp.uni-trier.de}
}