Turnstile Figures of Opposition
for the full version.
This paper has been presented at The 6th World Congress on the Square of Opposition
November 1-5, 2018, Orthodox Academy of Crete
it is inlcuded in the corrsepodning volume: J.-Y.Beziau and I.Vandoulakis (Eds.)
The Exoteric Square of Opposition
, Birkhäuser, Basel, 2021.