Gronmo, Sigmund. Social research methods : qualitative, quantitative and mixed methods approaches / Sigmund Gronmo. - 1st ed. - Thousand Oaks, CA ; London ; New Delhi : SAGE Publications, 2020. - 582 p. ; 25 cm. ISBN: 9781526441249 (pbk.) LCCN: 2019936648 Dewey Class. No.: 300.721 / GRO