Gay, L. R. Educational research : competencies for analysis and applications / L.R. Gay, Geoffrey E. Mills, Peter W. Airasian. - 9th ed. - Upper Saddle River, N.J. : Merrill/Pearson, c2009. - xvi, 618 p. : ill. ; 27 cm. Includes bibliographical references and index. ISBN: 9780132338776 0132338777 LCCN: 2008001686 Subjects--Topical Terms: Education--Research. LC Class. No.: LB1028 / .G37 2009 Dewey Class. No.: 370.7/2