, 2015, 'Is Euler's circle a symbol or an icon?', Sign systems studies 43 (4), 597-615.
with Schang, F. , 2015, On rules and refereeing in football, in A. Koslow & A. Buchsbaum (eds.), The road to universal logic II, Basel, Birkhäuser, pp. 407-415.
with Giardino, V. , Mols, S. , Van Bendegem, J. P. , 2012, 'Introduction: from practice to results in mathematics and logic', Philosophia Scientiae 16 (1), 5-11.
with Giardino, V. , Mols, S. , Van Bendegem, J. P. (eds) , 2012, Philosophia Scientiae 16 (1).
with Abeles, F. F. , 2011, 'Hugh MacColl and Lewis Carroll: crosscurrents in geometry and logic', Philosophia Scientiae 15 (1), 55-76.
with Read, S. , 2011, 'Preface', Philosophia Scientiae 15 (1), 1-5.
with Read, S. (eds) , 2011a, Philosophia Scientiae 15 (1).