TY  - BOOK
AU  - Welford, W. T
TI  - Aberrations of the symmetrical optical system
SN  - 0-12-742050-9
PY  - 1974///
CY  - London
PB  - Academic Press
KW  -  Aberrations
KW  -  Optics 
KW  - Astronomy and Astrophysics Thesaurus 
ER  -