TY  - BOOK
AU  - Walker, Gordon.
TI  - Astronomical observations : an Optical perspective / 
SN  - 0 521 33907 3
U1  - CogB9 
PY  - 1998///7
CY  - New York,N. Y-10011 : 
PB  - Cambridge University Press , 
KW  -  Physics
ER  -