Javier Legris
(2015)., On universality and formality in 19th century symbolic logic: the case of Schröder's "absolute algebra", in A. Koslow & A. Buchsbaum (eds.), The road to universal logic I, Basel, Birkhäuser, pp. 351-359.
(2005). On the epistemological justification of Hilbert's metamathematics. Philosophia Scientiae 9 (2), pp. 225-238.