How to Read and Why by Harold Bloom: “"Tlon, Ugbar, Orbis Tertius" begins with a disarming sentence (in Andrew Hurley's eloquent translation): "I owe the discovery of Ugbar to the conjunction of a mirror and an encyclopedia."”
On Literature by Umberto Eco: “discussed regarding Borges and the Rosicrucians”
Words Are My Matter by Ursula K. Le Guin: “...as the end of the story "Tlön, Uqbar, Orbis Tertius" suggests, we are now living there.”