Lewis F. Richardson (1961). «The problem of contiguity: An appendix to Statistics of Deadly Quarrels». General Systems: Yearbook of the Society for the Advancement of General Systems Theory. (Ann Arbor, Mich.: The Society, [1956–: Society for General Systems Research) 6 (139): 139–187. ISSN0072-0798. OCLC1429672. «In the previous section integrals were taken around simple geometrical figures, as a preliminary to taking them around frontiers shown on political maps. An embarrassing doubt arose as to whether actual frontiers were so intricate as to invalidate that otherwise promising theory. A special investigation was made to settle this question. Some strange features came to notice; nevertheless an over-all general correction was found possible. The results will now be reported. ... As an explanation of how chance can arise in a world which he regarded as strictly deterministic, Heri Poincare* (no date) drew attention to insignificant causes which produced very noticeable effects. Sea coasts provide an apt illustration.»
