ردهها Extended logics Classical logic 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Clarence Irving Lewis Cooper Harold Langford Symbolic Logic (Book) Saul Kripke A Completeness Theorem in Modal Logic Semantical Considerations on Modal Logic George Edward Hughes Maxwell John Cresswell An Introduction to Modal Logic A New Introduction to Modal Logic Modallogik نمونهها/پیادهسازیها Modal System T Modal System K Lewis's system S2 Lewis's system S1