TY  - BOOK
AU  - Keitz, H. A. E.
TI  -  Light calculations and measurements: an introduction to the syst em of quantities and units in light-technology and to photometry 
U1  - 535.2  22
PY  - 1955///
CY  - Eindhoven
PB  - Philips Technical Library
KW  - Photometry
ER  -