TY  - BOOK
AU  - Hughes,G.E.
AU  - Cresswell,M.J.
TI  - An introduction to modal logic
AV  - BC199.M6 H8
U1  - 160 
PY  - 1968///
CY  - London
PB  - Methuen
KW  - Modality Logic
KW  - Local
N1  - Bibliography: p. 356-371
ER  -