Nelkon, M.  1914 <br/><br/>
Light and sound / 
by M. Nelkon 
 - 4th. ed (with S1 units) 
 - London :  Heinemann Educational Books Ltd,  1969 
 - 418 p. ;  22 cm. 
<br/><br/><label>ISBN: </label>0435686143 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Light