Mishnà su Levitico 12:8

When is this so? When obligatory offerings [get mixed up] with voluntary offerings. When, however, obligatory offerings get mixed up one with another, with one [pair] belonging to one [woman] and the other pair to another [woman], or two [pairs] belonging to one and two [pairs] to another, or three [pairs] to one and three [pairs] to another, then half of these are valid and the other half disqualified. If one [pair] belongs to one [woman] and two pairs to another, or three pairs to another, or ten pairs to another or one hundred to another, only the lesser number remains valid. Whether they are of the same denomination or of two denominations, or whether they belong to one woman or to two.

What is meant by one "name"? For a birth and a birth, or for zivah and zivah, that is one name. And "two names"? For a birth, [and the other] for a zivah. What is meant by "two women"? [When] one [woman] brings [her offering] for a birth and the other for a birth, or [when one brings] for a zivah and the other for a zivah this is "of one name". And a case "of two names"? When one brings for a birth and the other for a zivah. Rabbi Yose says: when two women purchased their kinnim in partnership, or gave the price of their kinnim to the priest [for him to purchase them], then the priest can offer whichever one he wants as a hatat or as an olah, whether they are of one name or of two names.

If a woman says: "I vow a pair of birds if I give birth to a male child," and she does give birth to a male child, then she must offer up two pairs one for her vow and one for her obligation. If [before she assigned them] she gave them to the priest, and the priest who ought to offer three birds above and one below does not do so, but offers two above and two below, and does not seek guidance, she must she bring another bird and offer that above. This is so if the birds were of the same kind. If they were of two kinds, then must she bring two others. If she had expressly defined her vow, then must she bring three other birds. This is so if the birds were of the same kind. If they were of two kinds, then must she bring four others. If she made a definite fixture at the time of her vow, then must she bring another five birds. This is so if the birds were of the same kind. If they were of two kinds, then must she bring six others. If she gave them to the priest and it is not known what she gave, and the priest performed the sacrifice, but it is not known how he performed it, then she must bring four other birds for her vow, and two for her obligation and one for her hatat. Ben Azzai says: [she must bring] two hatats. Rabbi Joshua said: This is what it meant when they said: "When [the beast] is alive it possesses one sound, but when it is dead its sound is sevenfold." In what way is its sound sevenfold? Its two horns [are made into] two trumpets, its two leg-bones into two flutes, its hide into a drum, its entrails for lyres and its large intestines for harp strings; and there are some who add that its wool is used for the blue [pomegranates.] Rabbi Shimon ben Akashiah says: ignorant old people, the older they become, the more their intellect gets befuddled, as it is said: "He removes the speech of men of trust and takes away the sense of the elders." But when it comes to aged scholars, it is not so. On the contrary, the older they get, the more their mind becomes composed, as it is said: "With aged men comes wisdom, and understanding in length of days."