The following abbreviations are used for primary sources.
Charles S. Peirce
CN volume:page. Charles Sanders Peirce: Contributions to The Nation. 4 vols. ed. Kenneth L. Ketner and James E. Cook. Lubbock: Texas Tech University Press, 1975–87.
CP volume.paragraph. The Collected Papers of Charles Sanders Peirce. 8 vols. Vols. 1–6, ed. Charles Hartshorne and Paul Weiss. Vols. 7–8, ed. Arthur W. Burks. Cambridge, Mass.: Harvard University Press, 1931–58.
EP volume:page. The Essential Peirce: Selected Philosophical Writings. 2 vols. Vol. 1. ed. Nathan Houser and Christian Kloesel. Vol. 2, ed. Peirce Edition Project. Bloomington: Indiana University Press, 1992–98.
NEM volume:page. The New Elements of Mathematics. 4 vols. in 5, ed. Carolyn Eisele. The Hague: Mouton, 1976.
R (RL for letters) followed by Robin catalogue and sheet number. Manuscripts held in the Houghton Library of Harvard University, as identified by Richard Robin, Annotated Catalogue of the Papers of Charles S. Peirce. Amherst: University of Massachusetts Press, 1967, and in Richard Robin, “The Peirce Papers: A Supplementary Catalogue,” Transactions of the C. S. Peirce Society 7 (1971): 37–57.
RLT. Reasoning and the Logic of Things: The Cambridge Conferences Lectures of 1898, ed. Kenneth L. Ketner. Cambridge, Mass.: Harvard University Press, 1992.
SS. Semiotic and Significs: The Correspondence between Charles S. Peirce and Victoria Lady Welby, ed. Charles S. Hardwick. Bloomington: Indiana University Press, 1977.