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 (pp. 351-359). Basel: Birkhäuser.
(2005). On the epistemological justification of Hilbert's metamathematics. Philosophia Scientiae, 9 (2), 225-238. https://doi.org/10.4000/philosophiascientiae.540.