TY  - BOOK
AU  - D R & Khanna and H R Gulati 
AU  - Khanna, D R &    Gulati, H R 
TI  - Fundamentals of optics 
U1  - 535.2, KHA  
PY  - 1989///
CY  - New Delhi
PB  - R.Chand & Co
ER  -