Graves, John Thomas (J.T.G.). «Hyginus, gromaticus». A: William Smith. Dictionary of Greek and Roman Biography and Mythology (en anglès). vol. vol.1. Boston: Walton and Maberly, 1848 (1873) [Consulta: 12 agost 2015 (2015-08-12)]. «The Gromatici derived their name from the groma or gnomon [...].»