Recursive complexity of the Carnap first order modal logic C.

Amélie Gheerbrant Marcin Mostowski Recursive complexity of the Carnap first order modal logic C. 87-94 2006 52 Math. Log. Q. 1 http://dx.doi.org/10.1002/malq.200410057 db/journals/mlq/mlq52.html#GheerbrantM06