Leedy, Paul D. Practical research : planning and design / Paul D. Leedy, Jeanne Ellis Ormrod. - 8th ed. - Upper Saddle River, N.J. : Pearson Merrill Prentice Hall, 2005. - xxiii, 319 p. : ill. ; 28 cm. Includes index. Includes bibliographical references. ISBN: 0131247204 (pbk. ) Subjects--Topical Terms: Research--Methodology.