Engineering economy 
Sta. Maria, Hipolito B. 
 - Fourth edition. 
 -  National Book Store.  2014 
 - 179 pages. 
<br/><br/>
<br/><br/><label>ISBN: </label>9-71087202-8 
<br/><br/><label>Dewey Class. No.: </label>F620 S7751 2014