Sphaerica
Theodosius of Bithynia
Theodosius. Theodosii Tripolitae. Sphaericorum Libros Tres. Nizze, Ernst, editor. Berlin: G. Reimer, 1852.
Ἐν σφαίρᾳ κύκλοι ἐφάπτεσθαι ἀλλήλων λέγονται, ὅταν ἡ κοινὴ τομὴ τῶν ἐπιπέδων ἀμφοτέρων τῶν κύκλων ἐφάπτηται.
Theodosius. Theodosii Tripolitae. Sphaericorum Libros Tres. Nizze, Ernst, editor. Berlin: G. Reimer, 1852.
Ἐν σφαίρᾳ κύκλοι ἐφάπτεσθαι ἀλλήλων λέγονται, ὅταν ἡ κοινὴ τομὴ τῶν ἐπιπέδων ἀμφοτέρων τῶν κύκλων ἐφάπτηται.