Extended Strong's Greek Lexicon (Abbott-Smith based)
second-first
Usage: δευτερό-πρωτος, -ον second first (in what sense, there is no satisfactory explanation. The reading is prob. not original, see ICC, in l.; DCG, i, 411; ii, 541, 724): Luk.6:1, WH, mg., R, mg.† (AS)