Presocratics

Diels, H. and W. Kranz (eds.), 1903, Die Fragmente der Vorsokratiker, 3 volumes, Berlin:  Weidmannsche Buchhandlung.

Fragments des Présocratiques (Presocratic fragments), in French, maintained by Gé Journée, Centre Léon Robin, Paris IV-ENS website allows the consultation of a database aimed at first gathering ancient sources relating to philosophers who are known as presocratic.