Interpreting Qualitative Data : A guide to the principles of qualitative research / Silverman, David . _ - 4th Edition . _ - Los Angeles : SAGE publications, c2011 - xv, 500 pages : ill. ; 24 cm. includes bibliographical references and indexes ISBN: 978-0-85702-421-3 Subjects--Topical Terms: --Qualitative Research Dewey Class. No.: 300.72 SIL