දර්ශක සහ ලඝු ගණක 

 -  NIE,  1989 
 - 60p.;  ill.;  28cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Science-Maths
<br/><br/><label>Index Terms--Curriculum Objective: </label><br/>Distance Education