APA
Stewart D. W., Shamdasani P. N., . (1990). Focus groups. London: SAGE Publications.
Chicago
Stewart David W, Shamdasani Prem N, . 1990. Focus groups. London: SAGE Publications.
Harvard
Stewart D. W., Shamdasani P. N., . (1990). Focus groups. London: SAGE Publications.
MLA
Stewart David W, Shamdasani Prem N, . Focus groups. London: SAGE Publications. 1990.