Kerlinger, Fred Nichols, 1910-
Harcourt Brace College Publishers, 1973
Buku Teks
Kerlinger, Fred Nichols, 1910-
Holt, Rinehart and Winston, 1964
Buku Teks
Kerlinger, Fred Nichols, 1910-
Harcourt Brace College Publishers, 1992
Buku Teks
Luchins, Abraham S.
Holt, Rinehart and Winston, 1965
Buku Teks
Nieswiadomy, Rose Marie
Prentice-Hall, 2002
Buku Teks