@MISC{PROCAL_1.MIZ,
  AUTHOR = {Popio{\l}ek, Jan and Trybulec, Andrzej},
  TITLE = {Calculus of Propositions},
  DAY = {23},
  MONTH = {October},
  YEAR = {1990},
  ADDRESS1 = {Warsaw University\\Bia{\l}ystok},
  ADDRESS2 = {Warsaw University\\Bia{\l}ystok},
  SUMMARY = {     Continues the analysis of classical
language of first order (see \cite{QC_LANG1.ABS}, \cite{QC_LANG2.ABS},
 \cite{CQC_LANG.ABS}, \cite{CQC_THE1.ABS}, \cite{LUKASI_1.ABS}).
Three connectives: truth, negation and conjuction are primary
(see \cite{QC_LANG1.ABS}). The others (alternative, implication and equivalence)
are defined with respect to them (see \cite{QC_LANG2.ABS}).
We prove some important tautologies of the calculus of propositions.
Most of them are given as the axioms of classical logical calculus (see
  \cite{GRZEG1}). In the last part of our article we give some basic rules of inference.}}


@BOOK{GRZEG1,
       AUTHOR = {Andrzej Grzegorczyk},
        TITLE = {Zarys logiki matematycznej},
    PUBLISHER = {PWN},
         YEAR = {1973},
      ADDRESS = {Warsaw}}
