Gentzen-Prawitz Natural Deduction as a Teaching Tool

Jean-François Monin Cristian Ene Michaël Périn Gentzen-Prawitz Natural Deduction as a Teaching Tool http://arxiv.org/abs/0907.3599 2009 CoRR abs/0907.3599 db/journals/corr/corr0907.html#abs-0907-3599 informal publication