, 2018, Unlocking legal validity: some remarks on the artificial ontology of law, in P. Westerman, J. Hage, S. Kirste & A. R. Mackor (eds.), Legal validity and soft law, Dordrecht, Springer, pp. 99-123.
, 2015a, To whom does the law speak?: canvassing a neglected picture of law's interpretive field, in M. Araszkiewicz, P. Banaś, T. Gizbert-Studnicki & K. Płeszka (eds.), Problems of normativity, rules and rule-following, Dordrecht, Springer, pp. 265-280.