Johnston, C. L. <br/><br/>
Essential algebra  
C.L. Johnston, Alden T. Willis, Jeanne Lazaris. 
 - 5th ed. 
 - Belmont, Calif. :  Wadsworth Pub. Co.,  1988. 
 - 683p.:  ill. ;  28cm. 
 - The Johnston/Willis developmental mathematics series .
 - Johnston, C. L.  1911-  (Carol Lee),  Johnston/Willis developmental mathematics series. .