implied by Johannes Kepler (cynosurae septem stellas consideravit quibus cursum navigationis dirigebant Phoenices): "Notae ad Scaligeri Diatribam de Aequinoctiis" in Kepleri Opera Omnia ed. Ch. Frisch, vol. 8.1 (1870) p. 290
Gemmae Frisii de astrolabo catholico liber: quo latissime patentis instrumenti multiplex usus explicatur, & quicquid uspiam rerum mathematicarum tradi possit continetur, Steelsius (1556), p. 20
tufts.edu
perseus.tufts.edu
κυνόσουρα. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.