Practical research: : planning and design/ 
Leedy, Paul D. 
 - 10th edition. 
 -  Pearson Education Limited ,  2014 
 - 374 p. 
978-1-29202117-1
Research -- Methodology.
001.4 L484 2014
                        978-1-29202117-1
Research -- Methodology.
001.4 L484 2014