OPEN University of Sri Lanka <br/><br/>
Course of study leading to the degree of bachelor of science level 4- PSU 2114 O 

 - Nugegoda  The Open University of Sri Lanka  1986 
 - iii, 161 p. 
<br/><br/><label>ISBN: </label>102995 
<br/><br/><label>Dewey Class. No.: </label>547.6  / OPE