 Stoic contributions to logic and philosophy of language, as well as the backdrop of Aristotelian and Megarian views in the Hellenistic period, are thoroughly surveyed in a 100 page entry on the subject by Barnes, Bobzien and Mignucci in The Cambridge History of Hellenistic Philosophy (Algra et al, 1999). An abbreviated and more digestible version of this material by Bobzien appears in Inwood (2003).