J. H. Flavell, P. H. Miller, & S. A. Miller (2001). Cognitive Development. Prentice hall. Inc.
D. Moshman (1990). The Development of Metalogical Understanding. In W. F. Overton (Eds.), Reasoning, necessity, and logic: Development perspectives.
D. Moshman, & L. E. Lukin (1989). The Creative Construction of Rationality : A Paradox? In J. A. Glover, R. R Ronning, and C. R. Reynolds (Eds.), Handbook of Creativity. New York : Plenum.
J. Piaget (1987). Possibility and Necessity. Volume 1. & 2.. The Role of Possibility in Cognitive Development MN : University of Minnesota Press.