Reference for Avodah Zarah 64:5

והיוצא אסור מפני שהוא כזבחי מתים: מ"ט אי אפשר דליכא תקרובת עבודת כוכבים מני רבי יהודה בן בתירא היא

But that which is brought out is forbidden, because it is regarded as sacrifices of the dead. What is the reason? Because it is impossible for some idolatrous sacrifice not to have taken place. Whose opinion is this? That of R. Judah b. Batera;

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