Sahih Bukhari Volume 003, Book 039, Hadith Number 521.
Narated By 'Abdullah bin 'Umar : The Prophet concluded a contract with the people of Khaibar to utilize the land on the condition that half the products of fruits or vegetation would be their share. The Prophet used to give his wives one hundred Wasqs each, eighty Wasqs of dates and twenty Wasqs of barley. (When 'Umar became the Caliph) he gave the wives of the Prophet the option of either having the land and water as their shares, or carrying on the previous practice. Some of them chose the land and some chose the Wasqs, and 'Aisha chose the land.