Fowles, Grant R.
Thomson Brooks/Cole,, 1985
Buku Teks SO
Fowles, Grant R.
Holt, Rinehart, and Winston, 1977
Buku Teks SO
Singarimbun, Masri, translator
University of Illinois Press, 1964
Buku Teks
Parks
Buku Teks
Detton, Alan L. author
Wolters Kluwer, cop, 2017
Buku Teks SO