OPEN University of Sri Lanka <br/><br/>
Course of study leading to the degree of bachelor of science, level 5 PSU 3121-o 

 - Nugegoda  Open University of Sri Lanka  1988 
 - 31 p. 
<br/><br/><label>ISBN: </label>123724 
<br/><br/><label>Dewey Class. No.: </label>547.73  / OPE