OPEN University of Sri Lanka <br/><br/>
Course of study leading to the degree of bachelor of science level 4-PSU 2115-ph 

 - Nugegoda  The Open University of Sri Lanka  1987 
 - 82 p. 
<br/><br/><label>ISBN: </label>103015 
<br/><br/><label>Dewey Class. No.: </label>541.35  / OPE