Muwatta Imam Malik (Riwayat Yahya)

Imam Malik, may Allah have mercy on him, said: In our view, this ruling is agreed upon that uterine brothers and uterine sisters, when the deceased has children or the children of his son, that is, grandsons or granddaughters, or the deceased's father or grandfather is present, then they will be deprived of inheritance. However, if these people are not present, then they will receive inheritance. If there is one uterine brother or one uterine sister, he or she will receive one-sixth share. If there are two, each will receive one-sixth share. If there are more than two, then all will share in one-third of the wealth, dividing it equally. The sister will receive the same as the brother, because Allah, Glorious and Exalted is He, says: "If a man dies who is kalalah, or a woman dies being kalalah, and he has a brother or a sister (uterine, as in the recitation of Sayyiduna Sa'd ibn Abi Waqqas, may Allah be pleased with him), then each will receive one-sixth share. If there are more than that (i.e., one brother and one sister, or two sisters, two brothers, or more than that), then all will share in one-third." That is, men and women will all receive equally.