Reference for Niddah 41:36

אלא לאו לרבי יהודה ופליג

And were you to reply that R. Judah differs only in respect of red and black but not in that of green or white [the question would arise:] For whose benefit then was green and white mentioned? If it be suggested: For that of the Rabbis,<span class="x" onmousemove="('comment',' I.e., to indicate that the Rabbis regard the woman in such cases as clean. ');">³¹</span>

Jastrow