Cohen, Leon W., author
D. Van Nostrand, 1963
Buku Teks
Karauba, Anatolij A., author
Springer-Verlag, 1993
Buku Teks
Piaget, Jean, author
Routledge, 1952
Buku Teks
Adams, William W., author
Prentice-Hall, 1976
Buku Teks
Flath, Daniel E., author
John Wiley & Sons, 1989
Buku Teks