GreenBaggins has posted an article that provides a small piece of Turretin's writings on Justification (link). The article complains about the lack of free availability of Turretin in electronic form. It's worth noting that Turretin's magnum opus is freely available (link), but there is a catch: it's in the original Latin.
For more (in English) of Turretin on Justification:
Justification, Forensic or Moral? (answer: Forensic) (link) (second link) (third link)