Cicero, De natura deorum; numbering question

Dear list,

I have a minor but important (to me) question about the numbering of paragraphs and chapters in Cicero's De natura deorum: could anyone tell me from which early editions the two standard numbering systems that are in use derive? I have looked at some of the major modern editions for clues but this is probably considered a common knowledge by the editors. Could one be from Stephanus, as is common with other works?

Best,

Ivo Volt
University of Tartu, Estonia