Reference for Bava Batra 219:8
ואלא
AND SONS [INHERIT FROM, AND TRANSMIT TO THEIR] FATHER. Whence is this<span class="x" onmousemove="('comment',' That sons take precedence over daughters. ');"><sup>25</sup></span> derived? — It is written, <i>If a man die, [and have no son, then ye shall cause his inheritance to pass unto his daughter</i>].<span class="x" onmousemove="('comment',' Num. XXVII, 8. ');"><sup>26</sup></span> [From this it is to he inferred that] the reason<span class="x" onmousemove="('comment',' For causing the inheritance to pass to a daughter. ');"><sup>27</sup></span> is because he have no son but if he have a son the son takes precedence.<span class="x" onmousemove="('comment',' Over the daughter, who, however, according to a Rabbinical provision, is entitled, if unmarried to a tenth of the estate. Cf. Keth, 68a. ');"><sup>28</sup></span> R. Papa said to Abaye: Might it not be inferred<span class="x" onmousemove="('comment',' From Num. XXVII, 8. ');"><sup>29</sup></span> that if there be a son, the son is to be the heir; [if] there be a daughter, the daughter is to be the heir; [and if] there be [both] a son and a daughter, neither the one is to he heir nor the other? — But