Introduction to the Theory of Existential Graphs, Volumes 2/1 and 2/2Pietarinen, Ahti-VeikkoLogic of the future : writings on existential graphs. Part 1: The Logical Tracts2021 / p. 15-68 https://doi.org/10.1515/9783110651423-002

Introduction to the Theory of Existential Graphs, Volumes 2/1 and 2/2Pietarinen, Ahti-VeikkoLogic of the future : writings on existential graphs. Part 2: The 1903 Lowell Lectures2021 / p. 15-28 https://doi.org/10.1515/9783110740462-002