Leedy, Paul D. Practical research : planning and design / Paul D. Leedy, Jeanne Ellis Ormrod - 9th ed. - Upper Saddle River, NJ : Merrill, 2010 - xvii, 336 p. ; 28 cm. ISBN: 9780137152421 Subjects--Topical Terms: Research Dewey Class. No.: 001.4 / P895