Koller, L.R <br/><br/>
The physics of electron tubes 
L.R Koller 
 - London  Mcgraw-hill book company  1937 
 - 234 
<br/><br/> PE mean Physics, Electricity and Magnetism Page 450-456 in A to Z Register (Acc. No. Pe1-Pe205) 
<br/><br/><label>Dewey Class. No.: </label>PE110