Tosefta for Bekhorot 48:14

There is one who gives [the redemption payment] on his own behalf, there is one whose father gives on his behalf, there is one as to whom both he and his father give, [and there is one as to whom] neither he nor his father give. Which is the one who gives on his own behalf? [If] his conception was not in sanctity and his birth was not in sanctity (i.e., his mother had neither converted by conception or by childbirth), he gives on his own behalf. One as to whom there was a doubt if he was born nine months [after the death of] the previous [husband], or seven months [after her marriage to] the subsequent [husband], he gives on his own behalf. Two wives of two men who had never given birth, and they gave birth to two males in a hiding-place, and one of them died, the second one gives on his own behalf.
Which is the one whose father gives on his behalf? Two wives of two men who had never given birth, and they gave birth to two males in a hiding-place, this [man] gives five selas and that [man] gives five selas to the priest. [If] one father gave five selas and he died, the other father is liable, and the sons are exempt. [If] she and a priestess gave birth -- [or] she and a Levitess, [or] she and a woman who had already given birth -- [to two males], his father gives on his behalf. [If] one of them died, or if they were male and female, neither he nor his father give.
Which is the one as to whom both he and his father give? Two wives of two men who had never given birth, and they gave birth to two males in a hiding-place, this [man] gives five selas to the priest, and that [man] gives five selas to the priest. [If] one father gave five selas and died, the other father is liable, and the sons are exempt. [If] one of the sons died, the other son is liable, and the fathers are exempt. [If] one father gave five selas and [then] one of the sons died, behold, all of them are exempt. [If there were two women,] one who had given birth and one who had never birth, [married to] two men, and they gave birth to two males, and one one of them died within thirty days, behold, all of them are exempt.
Two wives of two men who had never given birth, and they gave birth to two males in a hiding-place, this [man] gives five selas to the priest, and that [man] gives five selas to the priest. [If] one father gave five selas to the priest and he died^*The printed text and MS Vienna read "and the sons died." However, this is not possible since they could not therefore be liable. Mitzpat Shmuel therefore references Bekh. 48a:2 (cf. Bekh. 8:3-8:4), involving the death of the father. before the sons had divided up their fathers' property, they are liable. Once they had divided up their fathers' property, they are exempt. Rabbi Yehuda says, even once they divided up their fathers' property, if this one had ten dinars from his father and that one had ten dinars from his father (see MS Vienna), they are liable, and if not, they are exempt. Two women who had never given birth, and they gave birth to two males in a hiding-place, [and the women] gave ten selas to the priest, [and] one of them (i.e., the sons) died within thirty days, they may take them (i.e., the selas) out of his hand. Rabbi Yehuda says, if they gave to one priest, they may take them out of his hand, [but] if they gave to two priests, they may not take them out of his hand, because the one who takes something from his fellow bears the burden of proof.