Per Martin-Löf
(2000-2009)
X(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, Dordrecht, Springer, pp. 209-219.
(2008)., The Hilbert-Brouwer controversy resolved?, in P. Boldini, M. Bourdeau & G. Heinzmann (eds.), One hundred years of intuitionism (1907–2007), Dordrecht, Springer, pp. 243-256.