Numbers 26:57-58

And these are those who were numbered of the Levites according to their families: of Gershon, the family of the Gershonites; of Kohath, the family of the Kohathites; of Merari, the family of the Merarites. These are the families of the Levites: the family of the Libnites, the family of the Hebronites, the family of the Mahlites, the family of the Mushites, and the family of the Korathites. And Kohath begot Amram.