, 2017a, Impossible colours: Wittgenstein and the naturalist's challenge, in M. Silva (ed.), How colours matter to philosophy, Dordrecht, Springer, pp. 107-121.
, 2017b, Incompatible colours and the development of Wittgenstein's philosophy, in M. Silva (ed.), Colours in the development of Wittgenstein's philosophy, Dordrecht, Springer, pp. 33-55.
, 1990, 'Pierre Duhem's conception of natural classification', Synthese 83 (3), 409-420.
, 1989a, History, discovery and induction: Whewell on Kepler on the orbit of mars, in J. Brown & J. Mittelstrass (eds.), An intimate relation, Dordrecht, Springer, pp. 283-298.