Nichols, Eugene D. <br/><br/>
Arithmetic of directed numbers: A programmed unit 

 - New York  Holt, Rinehart and Winston  1962 
 - 409p 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematics
<br/><br/><label>Dewey Class. No.: </label>513 NIC