Explicit Mathematics and Operational Set Theory: some Ontological comparisons. - Gerhard Jäger; Rico Zumbrunnen (Bull. Symb. Log., 2014)

A new model construction by making a detour via intuitionistic theories I: Operational set theory without choice is Π1-equivalent to KP. - Kentaro Sato; Rico Zumbrunnen (Ann. Pure Appl. Log., 2015)