DUEN-MIN DENG2018-09-102018-09-102016-03http://www.philo.ntu.edu.tw/review/?post_type=english&p=2109http://scholars.lib.ntu.edu.tw/handle/123456789/397936A Critical Comparison of Natural Deduction Systemsjournal article10.6276/NTUPR.2016.03.(51).02