Harder, Theodor. <br/><br/>
Introduction to mathematical models in market and opinion research 

 - Dordrecht :  Reidel,  1969 
 - 194 p. 
<br/><br/><label>LCCN: </label>73694 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mercadeo--Investigación.
<br/><br/><label>Dewey Class. No.: </label>658.83  / H3