OPEN University of Sri Lanka <br/><br/>
Course of study leading to the degree of bachelor of science- level 3 BTU 1201 p 

 - Nugegoda  The Open Univeristy of Sri Lanka  1984 
 - 91 p. 
<br/><br/><label>ISBN: </label>139142 
<br/><br/><label>Dewey Class. No.: </label>589.3  / OPE