Johnson, Norman
Voluntary social services
Martin Robertson, 1981
 Buku Teks
Busyra Azheri
Corporate social responsibility: dari voluntary menjadi mandatory
RajaGrafindo Persada, 2012
 Buku Teks SO
DeRosa, Thomas F.
Advance in polymer chemistry and methods reported in recent US patents
John Wiley & Sons, 2009
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Methods of research in social psychology
Elliot Aronson...[et al.]
McGraw-Hill, 1990
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Research methods in the social sciences
edited, Bridget Somekh, Cathy Lewin
Sage, 2005
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