  This paper considers a formalisation of classical logic using general
introduction rules and general elimination rules. It proposes a definition of
`maximal formula', `segment' and `maximal segment' suitable to the system, and
gives reduction procedures for them. It is then shown that deductions in the
system convert into normal form, i.e. deductions that contain neither maximal
formulas nor maximal segments, and that deductions in normal form satisfy the
subformula property. Tarski's Rule is treated as a general introduction rule
for implication. The general introduction rule for negation has a similar form.
Maximal formulas with implication or negation as main operator require
reduction procedures of a more intricate kind not present in normalisation for
intuitionist logic. The Correction added to the end of the paper corrects an
error: Theorem 2 is mistaken, and so is a corollary drawn from it as well as a
corollary that was concluded by the same mistake. Luckily this does not affect
the main result of the paper.
