Open university <br/><br/>
System behaviour 

 - Walton  Hall Open University         1977 
 - p.  cm. 
<br/><br/><label>Standard No.: </label>23710 
<br/><br/><label>Source: </label> Textual 
<br/><br/><label>Dewey Class. No.: </label>B4394, L7