TY  - BOOK
AU  - Hughes,G.E.
AU  - Cresswell,M.J.
TI  - A New Introduction to Modal Logic
SN  - 9780415126007
U1  - 160 
PY  - 1996///
CY  - London
PB  - Routledge
KW  - Modality (Logic)
ER  -