APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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