Shekhtman, V. B. Two-dimensional modal logic. (English) Zbl 0403.03015 Math. Notes 23, 417-424 (1978). MSC: 03B45 03C52 03C90 × Cite Format Result Cite Review PDF Full Text: DOI
Shekhtman, V. B. Zweidimensional modale Logiken. (Russian) Zbl 0384.03010 Mat. Zametki 23, 759-772 (1978). MSC: 03B45 03C52 03C90 × Cite Format Result Cite Review PDF