Peirce (1882), "Introductory Lecture on the Study of Logic" delivered September 1882, Johns Hopkins University Circulars, v. 2, n. 19, pp. 11–12 (via Google), November 1882.
web.archive.org
Peirce (1899 MS), "F.R.L." [First Rule of Logic], Collected Papers of Charles Sanders Peirce, 1.135–40, Eprint
