Bava Batra 158a (קנח.) — the Talmud in English

Mishna:

If the house collapsed upon him and upon his wife,

and she had no children from him [as children have precedence in inheritance], and it is not known who died first.

The husband’s heirs say: The wife died first,

and the husband inherited his wife; and after he too died, the property passes to his heirs, namely, his father or his brothers.

and

the wife’s heirs say: The husband died first,

and his right to inherit his wife lapsed,

and afterward the wife died,

and therefore her relatives from her father’s family wish to inherit her—

Beit Shammai say: They divide it

because of the uncertainty.

And Beit Hillel say: The assets

that are nakhsei tzon barzel, property whose value the husband acquired and whose value he must return to the wife when he divorces her or when he dies,

remain in their presumptive status,

and the Gemara will explain in whose presumptive possession they are.

The ketubah,

the hundred or two hundred dinars that the husband undertook to pay at the marriage—

is presumed to belong to the husband’s heirs,

since this is money that the husband must pay, and until now he was presumed to possess it; therefore, it remains in his presumptive possession.

Assets that enter and leave with her—

the nakhsei melog, property belonging to the wife whose usufruct the husband enjoys—

are presumed to belong to the father’s heirs.

They are the wife’s heirs, since the property belongs to her and she brought it from her father’s house; therefore, her heirs receive it.