I have a few commentaries on Luke (Marshall. NIGTC, Nolland (WBC), Robert Stein (NAC), J Reiling (UBS Handbook) and others. My professor said I needed to use Bock in BECNT and Fitzmeyer in Anchor Bible for Luke's Gospel. He said these were the best for finding future research trends. I am looking to cultivate deeper but I do not have much money and these two sources are only suggested in the syllabus. Can someone explain this to me?