TY  - GEN
AU  - Jayasinghe , E.M.
AU  - jayaratne , Osmund
TI  - Waves and vibrations 
U1  - 531.32 
PY  - 1984///
CY  - Nugegoda
PB  - Open university
KW  - Physics
KW  - Waves and vibrations
ER  -