The view of Al-Manzileen and Abu Yusuf regarding the inheritance of the son of a sister (ibn ukht) versus the daughter of a sister (bint ukht) when only they inherit from the sister.
Chapter on Distant Kindred (Dhawu al-Arham)
Al-Mughni
Book of Inheritance Shares (Farā'id)
Primary text
There is no disagreement between Al-Manzileen regarding the first case, as each one of them inherits through the person through whom they are related. This is also the opinion of Muhammad ibn al-Hasan. Abu Yusuf requires them to be considered in themselves, making the son of the sister entitled to two-thirds and the daughter of the sister to one-third.
Supporting text
In the second case, there is no disagreement between Al-Manzileen that the offspring of each sister inherits her share, which is one-half. Those who diverge grant half the inheritance divided equally between the son of the sister and his sister, and the other half to the daughter of the other sister, solving the case from four shares. Those who favor the minority divide the half between them into three, solving the case from six.