OPEN University of Sri Lanka <br/><br/>
Course of study leading to the degree of bachelor of science level 5 PSU 3120- o 

 - Nugegoda  Open University of Sri Lanka  1989 
 - 61 p. 
<br/><br/><label>ISBN: </label>123722 
<br/><br/><label>Dewey Class. No.: </label>547  / OPE