Gaya APA

Duska, R, D, M, W. (1977). Moral development, a guide to Piaget and Kohlberg. . [Dublin]: Gill and Macmillan.

Gaya MLA

Duska, Ronald, Dan, Mariellen, Whelan.. "Moral development, a guide to Piaget and Kohlberg. ". [Dublin]: Gill and Macmillan, 1977. Buku.