OPEN University of Sri Lanka <br/><br/>
Couses of study leading to the degree of bachelor of science-level 5 PSU 3119: t 

 - Nugegoda  Open University of Sri Lanka  1990 
 - 55 p. 
<br/><br/><label>ISBN: </label>123706 
<br/><br/><label>Dewey Class. No.: </label>664.33  / OPE