, 2012a, 'Faith, unbelief and evil: a fragment of a dialogue', Synthese 188 (3), 381-397.
, 2012b, 'The fable of the four preachers', Synthese 188 (3), 455-457.
, 2012c, 'The logic of obligation and the obligations of the logician', Synthese 188 (3), 423-448.
, 2012d, 'The paradox of the prisoner in logical form', Synthese 188 (3), 411-416.
, 1968a, Imperatives and truth, in L. Gabriel (ed.), Kolloquien, Freiburg-Basel-Wien, Herder, pp. 291-296.
, 1968b, The logic of tenses, in L. Gabriel (ed.), Kolloquien, Freiburg-Basel-Wien, Herder, pp. 638-640.
with Kneale, W. , 1968, 'Intentionality and intensionality', Proceedings of the Aristotelian Society 42, 73-100.
with Feys, R. , 1956a, 'A note on the logic of obligation', Revue philosophique de Louvain 54 (41), 86-89.