Palys, T.S. (Theodore Stephen)
Research decisions : quantitative, qualitative, and mixed method approaches
Nelson Education, 2014
 Buku Teks SO
Creswell, John W.
Research design : qualitative, quantitative, and mixed methods approaches
Sage Publication, Inc, 2003
 Buku Teks SO
Creswell, John W.
Research design : qualitative, quantitative, and mixed methods approaches
Sage, 2014
 Buku Teks SO
Creswell, John W.
Research design : qualitative, quantitative, and mixed methods approaches
Sage, 2018
 Buku Teks SO
Creswell, John W.
Research design : Pendekatan metode kualitatif, kuantitatif, dan campuran
Pustaka Pelajar, 2017
 Buku Teks SO