TY  - BOOK
AU  - J.B. Heaton, D.F. Clarke 
AU  - J.B. Heaton, D.F. Clarke 
TI  - Communication Targets (Book Tur) 
U1  - 420/H437c 
PY  - 1982///
CY  -  singapur
PB  - Longman,, 
ER  -