It is well known that Bradwardine's magnum opus De causa Dei was heavily influenced by Augustine's De civitate Dei, but scholars rarely if ever mention the obvious parallel between the two titles. From a quick survey, the best I can find is an incidental comment in Minnis and Johnson's introduction to The Cambridge History of Literary Criticism vol. 2 (2005): ‘the prosimetric elegance of Thomas Bradwardine's De causa Dei (written in proud imitation of Augustine's De civitate Dei)’.
The full title of Augustine's work is De civitate Dei contra Paganos. Bradwardine's work is usually cited as De causa Dei contra Pelagium, but sometimes as De causa Dei contra Pelagianos. If Bradwardine's title is a homage to Augustine, shouldn't that count in favour of the second version? Just a thought.