Per Martin-Löf
(2013). Verificationism then and now. In M. Van Der Schaar (ed.) Judgement and the epistemic foundation of logic (pp. 3-14). Dordrecht: Springer.
(2009). 100 years of Zermelo's axiom of choice: what was the problem with it?. In E. Palmgren & K. Segerberg (eds.) Logicism, intuitionism, and formalism (pp. 209-219). Dordrecht: Springer.
(2008). The Hilbert-Brouwer controversy resolved?. In P. Boldini, M. Bourdeau & G. Heinzmann (eds.) One hundred years of intuitionism (1907–2007) (pp. 243-256). Dordrecht: Springer.
(1995). Verificationism then and now. In W. Depauli Schimanovich, E. Köhler & F. Stadler (eds.) The foundational debate (pp. 187-196). Dordrecht: Springer.
(1994). Analytic and synthetic judgements in type theory. In P. Parrini (ed.) Kant and contemporary epistemology (pp. 87-99). Dordrecht: Springer.
(1987). Truth of a proposition, evidence of a judgement, validity of a proof. Synthese, 73 (3), 407-420. https://doi.org/10.1007/BF00484985.