Reference for Chullin 227:41

אשכחן אחותו גדולה אחותו קטנה מנין

We have thus learnt [the prohibition with regard to] 'the older sister', but whence do we know it with regard to 'the younger sister'?<span class="x" onmousemove="('comment',' V. supra p. 626, n. 20.');">¹⁷</span>

Jastrow