@article{106236, author = {Jan Kraj\'\i \v cek}, title = {A possible modal reformulation of comprehension scheme}, journal = {Commentationes Mathematicae Universitatis Carolinae}, volume = {024}, year = {1983}, pages = {387-388}, language = {en}, url = {http://dml.mathdoc.fr/item/106236} }
Krajíček, Jan. A possible modal reformulation of comprehension scheme. Commentationes Mathematicae Universitatis Carolinae, Tome 024 (1983) pp. 387-388. http://gdmltest.u-ga.fr/item/106236/
An introduction to modal logic, Methuen and Co. Ltd., 1968. (1968) | MR 0439586