Reference for Sotah 39:1

קשיא דר' עקיבא אדרבי עקיבא התם אמר מחיקה מעכבא והכא אמר קומץ מעכב

But R. Akiba [nevertheless] contradicts himself; he declared above that it was the obliteration [of the inscription] which prevents [her from retracting], and here he declares that [the offering of the] handful prevents her! — There are two Tannaim [who take opposite sides on this question] in the view of R. Akiba.

Jastrow

Jastrow