Cita APA (7th ed.)

Wittgenstein, L. (1971). Prototractatus: An early version of Tractatus logico-philosophicus. Routledge & Kegan Paul.

Cita Chicago (17th ed.)

Wittgenstein, Ludwig. Prototractatus: An Early Version of Tractatus Logico-philosophicus. London: Routledge & Kegan Paul, 1971.

Cita MLA (9th ed.)

Wittgenstein, Ludwig. Prototractatus: An Early Version of Tractatus Logico-philosophicus. Routledge & Kegan Paul, 1971.