Musannaf Ibn Abi Shaybah

A'mash narrates that Hazrat Abdullah (may Allah be pleased with him) used to distribute inheritance in the case of a daughter, granddaughter, grandsons, sons of full sisters, and sons and daughters of half-siblings in such a way that he would give half of the wealth to the daughter. Then he would see, if enough wealth remained to be given to the males so that they would receive more than one-sixth, he would not give them more than one-sixth. And if they received less than one-sixth, he would give it to them and would not consider it a loss. And other companions of the Prophet (may Allah be pleased with them) used to say that for this woman, half of the wealth is due, and the remaining wealth should be distributed in such a way that one male receives the share equal to that of two females. Hazrat Abu Bakr (may Allah be pleased with him) said that the basis of this issue will be derived from the number six.