Reference for Bava Batra 228:3

הא קא משמע לן דאשה את בנה דומיא דאשה את בעלה מה אשה את בעלה אין הבעל יורש את אשתו בקבר אף אשה את בנה אין הבן יורש את אמו בקבר להנחיל לאחין מן האב

and Half.<span class="x" onmousemove="('comment',' The case where a testator expressed the wish that his estate be divided between his wife and his son. The widow, according to R. Joseph, is entitled to half the estate (cf. infra 143a). ');">⁷</span> A WOMAN [TRANSMITS HER ESTATE TO] HER SONS etc. For what [purpose is] this [statement] also required? Surely it has been taught [already] in an earlier clause [that] A MAN [INHERITS FROM] HIS MOTHER AND [FROM] HIS WIFE!<span class="x" onmousemove="('comment',' Since the earlier clause enunciated the laws that a son inherits from, and does not transmit to his mother, and that a husband also inherits from, and does not transmit to his wife, what need is there for the clause stating that 'a woman transmits her estate to her son and to her husband, but does not inherit from them', which, though in different words, is a mere repetition of the laws in the earlier clause? ');">⁸</span> — It teaches us<span class="x" onmousemove="('comment',' By the addition of the superfluous clause. ');">⁹</span>

Jastrow