1. Wundt, Wilhelm Max Grundriss der Psychologie. Leipzig: Engelmann, 1896
2. Stephan, A. “Emergence – A Systematic View on Its Historical Facets.” In Emergence or Reduction? edited by A. Beckermann, H. Flohr, and J. Kim, pp. 25–48. Berlin: Walter de Gruyter, 1992
3. Selz, Otto “Die Umgestaltung der Grundanschauungen vom intellektuellen Geschehen.” In VIIIth International Congress of Psychology, pp. 413–414. Groningen. Reprinted in Kantstudien 32 (1927): 273–280. Translated as “The Revision of the Fundamental Conceptions of Intellectual Processes,” in Thinking: From Association to Gestalt, edited by J. M. Mandler and G. Mandler (New York: John Wiley and Sons, 1964), pp. 225–234
4. Popper, Karl The Myth of the Framework. London: Routledge, 1994
5. Popper, Karl “Of Clouds and Clocks.” In Objective Knowledge, pp. 206–235. Oxford: Clarendon Press, 1972