Monotone Subsequences in Any Dimension. - Ryan Siders (J. Comb. Theory A, 1999)

Register computations on ordinals. - Peter Koepke; Ryan Siders (Arch. Math. Log., 2008)

Minimality considerations for ordinal computers modeling constructibility. - Peter Koepke; Ryan Siders (Theor. Comput. Sci., 2008)

On quantifier-rank equivalence between linear orders. - Ryan Siders (Inf. Comput., 2010)