Stata Corporation <br/><br/>
Stata base reference manual; S - Z.   

 - Texas  Stata Press  2003 
 - V.4 - 391p. Bibl. Index. 
 - Statistics, graphics and data management .
<br/><br/> "Stata - Release 8"   
<br/><br/><label>ISBN: </label>1881228762 
<br/><br/><label>Dewey Class. No.: </label>518.5425  / St797.SB.4