There are a few PhDs waiting to be written on how New Testament manuscripts refer back to the Old Testament. At times they do a marvellous job. Have a look here at the margin of minuscule 1739 at Gal 3:12 (I was there because I had to check 3:13 οτι γεγραπται - γεγραπται γαρ).
The reference for ο ποιησας αυτα ανθρωπος ζησεται εν αυτοις is given as 'Deuteronomy and Ezekiel'. Of course this leaves out the exact citation as in Leviticus 18:5, but when it comes to Ezekiel, it is spot on. In this book the notion that 'someone will live' because he walks in the statutes is quite pervasive (chs 18, 20, 33). Well done, Ephraem!