Musannaf Ibn Abi Shayba 13:2114

Abu Bakr narrated to us, he said: 'Abdah bin Sulayman narrated to us, from Hasan bin Salih, from Ibn Abi Layla, Ibn Shubruma, and Rabi'ah al-Ra'y. They said regarding two men between whom there is a bag: one of them says, "Half of it is mine," and the other says, "All of it is mine." Ibn Shubruma said: For the one who said "All of it is mine," half of it is exclusively his, and what remains is between the two of them. Ibn Abi Layla said: Two-thirds of the wealth is [for the one who claimed all of it], because the owner of the half has absolved himself of the half. And the one who claims the half is given one-third, because the owner of the two-thirds has absolved himself of the third. A sixth remains, and both of them claim it, so it is between them in two halves.