1. Alfred North Whitehead, “The Analysis of Meaning”, Science and Philosophy (New York: Philosophical Library, 1948).
2. Bowman L. Clarke, “A Calculus of Individuals Based on’ Connection’”, Notre Dame Journal of Formal Logic 22 (July 1981): 204–217.
3. Bowman L. Clarke, “Individuals and Points”, Notre Dame Journal of Formal Logic 26 (January 1985): 61–75.
4. Theodore de Laguna, “Point, Line and Surface, As Sets of Solids”, The Journal of Philosophy, 19 (1922): 449–461.
5. Jean Nicod, Geometry and Induction (Berkeley: University of California Press, 1970), pp. 26–27.