The Cambridge companion to early greek philosophy - Long, Anthony A.; Taylor, C.C.W; McKirahan Jr., Richard D.; Sedley, David; Most, Glenn W.; Decleva Caizzi, Fernanda; Woodruff, Paul; Vegetti, Mario; Graham, Daniel W.; Huffman, Carl A.; Lesher, J. H.; Hussey, Edward; et al. (Cambridge University, 1999)