Reference for Chullin 248:16

עד כאן לא קא מטהר רבי עקיבא אלא בעור אבל בעלמא מטמא

As it is established that R'Dosa B'Harkinas is in agreement with R'Ishmael, it follows that the Sages [th opponents of R'Dosa] are in agreement with R'Akiba [the opponent of R'Ishmael].

Jastrow