Vyavasaya adhyyan : Vyavasaya, vitt evam vipnnan : Kaksha 12 ke liye pathyapustak 
NCERT (New Delhi India) 
 - New Delhi, India  National Council of Educational Research and Training  2007 
 - vi,253-439p 
<br/><br/><label>ISBN: </label>80-7450-760-4 
<br/><br/><label>Source: </label>Reference