Duffy, Tim <br/><br/>
Four software tools 

 - Wadsworth  1986 
 - 575 p.  PB  24 cm. 
<br/><br/><label>Subjects--Uniform Titles: </label><br/>PC-DOS (Computer file)<br/>MS-DOS (Computer file)<br/>Lotus 1-2-3 (Computer file)
<br/><br/><label>Dewey Class. No.: </label>005.36  / DUF