Helms, Ronald N. <br/><br/>
Illumination engineering for energy efficient luminous environments / 
Ronald N. Helms. 
 - Englewood Cliffs, N.J. :  Prentice-Hall,  c1980. 
 - xiii, 322 p. :  ill. 
<br/><br/><label>ISBN: </label>0134508092 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Electric lighting.<br/>Lighting.<br/>Electric power--Conservation