On JSTOR:
Paul Feyerabend, “Wittgenstein's Philosophical Investigations,” The Philosophical Review, vol. 64 (1955), pp. 449-483 (on JSTOR at 2182211)
Gottlob Frege, “Sense and Reference,” The Philosophical Review, M. Black (tr.), vol. 57 (1948), pp. 209-230 (on JSTOR at 2181485)
Gottlob Frege, “The Thought: A Logical Inquiry,” A. M. and M. Quinton (trs.), Mind, n.s. vol. 65 (1956), pp. 289-311 (on JSTOR at 2251513)
Bertrand Russell, “On Denoting,” Mind, n.s. vol. 14 (1905), pp. 479-493 (on JSTOR at 2248381)
Moritz Schlick, “Positivism and Realism,” D. Rynin (tr.), Synthese, vol. 7 (1948-49), pp. 478-505 (on JSTOR at 20114083)
Alfred Tarski, “The Semantic Conception of Truth: and the Foundations of Semantics,” Philosophy and Phenomenological Research, vol. 4 (1944), pp. 341-376 (on JSTOR at 2102968)
In PDF format (to be available on the website and Moodle):
Charles Sanders Peirce, “How to Make Our Ideas Clear,” Popular Science Monthly, vol. 12 (1877-78), pp. 286-302 (1up PDF, 2up PDF, booklet PDF)
Ludwig Wittgenstein, sels. from Tractatus Logico-Philosophicus, C. K. Ogden (tr.) (1up PDF, 2up PDF, booklet PDF)