Euclid's Elements, Book I, Definitions 11 and 12

Euclid : Book 1 : Definition 11 — Hive

Insights from Euclid's 'Elements' — LessWrong

Online table of contents for Euclid's Elements (Joyce, 1996; used

Euclid's Elements - Wikipedia

Euclid's Elements - Book 5: Definitions 11 through 13.

Mathematical Treasure: Robert Simson's The Elements of Euclid

Euclid's Elements of Geometry (1770s)

Euclid's Elements, Book XI, Definition 11

III. Diagrams after Samuel Cunn's Euclid's Elements of Geometry