BRICKEN, William, 2006. The Mathematics of Boundaries: A Beginning. In: BARKER-PLUMMER, Dave, COX, Richard and SWOBODA, Nik (eds.), Diagrammatic Representation and Inference. Berlin, Heidelberg: Springer. 2006. p. 70–72. Lecture Notes in Computer Science. ISBN 978-3-540-35624-0. DOI 10.1007/11783183_8.

> The intuitive properties of configurations of planar non-overlapping closed curves (boundaries) are presented as a pure boundary mathematics. The mathematics, which is not incorporated in any existing formalism, is constructed from first principles, that is, from empty space. When formulated as pattern equations, boundary algebras map to elementary logic and to integer arithmetic.