Das Asha <br/><br/>
Grah vigiyan: Patthyapustak aur prayogatmak pushtak 

 - New Delhi, India  Arya Book Depot  1995 
 - viii,323p. 
<br/><br/><br/>Barhavi kaksha ke liye 
<br/><br/><label>Source: </label>Textual