APA (7th ed.) Citation

Eco, U., & Marmo, C. (1989). On the Medieval theory of signs. Benjamins.

Chicago Style (17th ed.) Citation

Eco, Umberto, and Costantino Marmo. On the Medieval Theory of Signs. Amsterdam [etc.]: Benjamins, 1989.

MLA (9th ed.) Citation

Eco, Umberto, and Costantino Marmo. On the Medieval Theory of Signs. Benjamins, 1989.

Warning: These citations may not always be 100% accurate.