Consistency of Heyting arithmetic in natural deduction. - Annika Kanckos (Math. Log. Q., 2010)

Normal Derivability in Classical Natural Deduction. - Jan von Plato; Annika Siders (Rev. Symb. Log., 2012)

Gentzen's consistency proof without heightlines. - Annika Siders (Arch. Math. Log., 2013)

Normalization proof for Peano Arithmetic. - Annika Siders (Arch. Math. Log., 2015)

From Stenius' Consistency Proof to SCHüTTE's Cut Elimination for ω-Arithmetic. - Annika Siders (Rev. Symb. Log., 2016)

Variants of Gödel's Ontological Proof in a Natural Deduction Calculus. - Annika Kanckos; Bruno Woltzenlogel Paleo (Stud Logica, 2017)

A note on Gentzen's ordinal assignment. - Annika Kanckos (Arch. Math. Log., 2019)

The Development of Gödel's Ontological Proof. - Annika Kanckos; Tim Lethen (Rev. Symb. Log., 2021)

Intuitionistic Derivability in Anderson's Variant of the Ontological Argument. - Annika Kanckos (ARQNL@IJCAR, 2022)