Reference for Bekhorot 97:18

או דלמא

just as there [in the latter case] it says 'And upward' s here also in the case of redemption it means 'and upward'.<span class="x" onmousemove="('comment',' That redemption is strictly due only after the thirty days of the child's birth.');">¹⁶</span>

Jastrow

Jastrow